Documentary about the little known Yugoslav-American scientist Nikola Tesla, whose experiments with electricity and wireless foreshadowed the discoveries of Edison and Marconi. Some of his most spectacular experiments are recreated by the programme's presenter Robert Syme.

The Mysterious Mr. Tesla

Something weird seems to be happening to our weather - it appears to be getting more extreme. In the past few years we have shivered through two record-breaking cold winters and parts of the country have experienced intense droughts and torrential floods. It is a pattern that appears to be playing out across the globe. Hurricane chasers are recording bigger storms and in Texas, record-breaking rain has been followed by record-breaking drought. Horizon follows the scientists who are trying to understand what's been happening to our weather and investigates if these extremes are a taste of whats to come.

Global Weirding

Over the past year, Horizon has been behind the scenes at one of Britain's leading cancer hospitals, the Royal Marsden in London. The film follows Rosemary, Phil and Ray as they undergo remarkable new treatments - from a billion pound genetically targeted drug designed to fight a type of skin cancer, to advanced robotic surgery. We witness the breakthroughs in surgery and in scientific research that are offering new hope and helping to defeat a disease that more than one in three of us will develop at some stage of our lives.

Defeating Cancer

At the heart of the AIDS epidemic in Africa, there is a deadly mystery that has puzzled scientists for years. There are groups of people who are four times less likely to get HIV than other people, sometimes living just yards away, across a single valley - people with apparently similar behaviour and lifestyle. Scientists realised that if they could understand why these people are so much less vulnerable to the HIV virus, it might lead to an answer that could save millions of lives. And after 15 years of detective work it turns out there may be a remarkably simple answer: the high risk areas for HIV coincide with tribes who are uncircumcised. In Africa, it seems a man is much more likely to get HIV if he is uncircumcised.

In Kaoma, Western Zambia, a young boy is on his way to the sacred Mukondaa - the tribal circumcision ground. Around him the tribal elders are gathered, dressed in their ceremonial garb, and vivid masks. But the young boy himself is an outsider, not from this tribe, and none of his relatives or ancestors have ever been circumcised. In fact, his parents are only prepared to break the taboo of their own tribe because they believe that circumcision could save his life by protecting him from AIDS. At first sight this belief seems like the kind of superstition to which desperate people often turn in times of plague. But now there is scientific evidence that suggests these people could well be right.

There have now been twenty seven statistical studies that show a big difference in HIV infection between circumcised and uncircumcised men. For example, among the uncircumcised people of Kisumu in Western Kenya, a man is three times as likely to get AIDS than his circumcised neighbours. Among truck drivers in Mombasa the difference is four-fold.

Horizon travels across Africa, tracing the work of scientists who have unearthed the statistical data behind this correlation. At the same time microbiologists have been battling to understand the complex and insidious virus, and their work indicates that the foreskin may be a key entry point for HIV. The logical conclusion for these scientists is that if you remove the foreskin, you begin to protect the man. No-one believes that circumcision can protect completely - the evidence so far only indicates that it reduces the risk of infection by HIV, and then only during heterosexual sex. Unquestionably, condoms are still the best protection. But in the many countries where the use of condoms is minimal, it seems that circumcision might help to reduce the spread of AIDS.

In the absence of a vaccine for AIDS, and the lack of condom use in the developing world, should governments think the unthinkable and encourage the circumcision of young boys in non-circumcising tribes as a public policy? Opposing this idea are the voices of tribal elders who are loath to change tribal traditions that have existed for generations, and a fierce Western anti-circumcision lobby which believes that circumcision is a form of mutilation and violates basic human rights.

Valley of Life or Death

In this episode, Horizon looks at connections between crime and poor housing design in the USA.

The Writing on the Wall

Changes to the bacteria that live inside all of us are responsible for increasing the number of people with allergies, suggests new research. The show investigates this claim by conducting a unique experiment with two allergic families in order to find out just what it is in the modern world that is to blame. With a raft of mini cameras, GPS units and the very latest gene sequencing technology, the show discovers how the western lifestyle is impacting their bacteria. Why are these changes making people allergic? And what can be done to put a stop to the allergy epidemic?

Allergies: Modern Life and Me

Particle physicist Professor Brian Cox asks, 'What time is it?' It's a simple question and it sounds like it has a simple answer. But do we really know what it is that we're asking?

Brian visits the ancient Mayan pyramids in Mexico where the Maya built temples to time. He finds out that a day is never 24 hours and meets Earth's very own Director of Time. He journeys to the beginning of time, and goes beyond within the realms of string theory, and explores the very limit of time. He discovers that we not only travel through time at the speed of light, but the experience we feel as the passing of time could be an illusion.

Do You Know What Time It Is?

Horizon examines the design of Formula One racing cars with a particular reference to the aerodynamic 'skirt'.

Gentlemen, Lift Your Skirts

When and how did space and time begin? The birth of the Universe is one of the biggest mysteries in astronomy. It has perplexed the best scientific minds for centuries. Decades before space travel was possible, astronomers dreamed of putting a telescope into orbit to try and answer these fundamental questions. It wasn't until the 1970s, when space flight had become a reality, that NASA resolved to build just such a space telescope. They named it Hubble.

This was one of the most ambitious missions ever conceived. The technical challenges were enormous and it took 12 years to design and build. Travelling at seventeen thousand miles an hour, the Hubble Telescope would take pictures of the furthest reaches of space, transmitting them 400 miles back to Earth.

In April 1990 the Hubble Space Telescope was launched. But just weeks later, disaster struck - the $2 billion telescope had a fatal flaw in its main mirror. This was not just a disaster for NASA; it was a national scandal. Hubble had to be saved; scientists and engineers began to search desperately for a solution to the problem.

Plans for an adventurous repair mission began to take shape but it was two years before work could be carried out. It took astronauts five gruelling space-walks to carefully replace the instruments and patch up the telescope. But nobody knew if Hubble would be able to deliver on any of its original promises.

Finally, the miracle happened. An unexpected avalanche of data from Hubble confirmed that the telescope was fixed. At last it began to solve the most fundamental puzzles of the Universe.

Hubble has given us breathtaking images of the birth of stars; it has found black holes swallowing matter at the centre of galaxies; and last year the Hubble Telescope resolved the most fundamental question in astronomy - the age of the Universe. At last, half a century of scientific endeavour was rewarded.

Horizon marks the 10th anniversary of the launch of the Hubble Space Telescope by tracing the extraordinary tale of triumph, disaster and eventual success of this unique window into the Universe.

Miracle In Orbit

Horizon puts Graham Hancock's controversial theories about the past to the test, dissecting his evidence for a lost civilisation.

Graham Hancock offers various pieces of evidence to support his theory. He claims that the mysterious lost civilisation left its mark in ancient monuments, which he calculates were built to mirror certain constellations of stars. His hugely popular ideas have attracted such a wide audience that they stand to replace the conventional view of the past, which is based on scientific evidence that the civilisations of the ancient world were developed independently, by different peoples, on different continents.

Atlantis Reborn Again

A trail from Greenland to Britain via Latvia offers new evidence into how evolution could have seen aquatic life form legs and walk.

The Missing Link

Horizon examines the concept and implications of a global village in Third World countries.

Global Village

Horizon investigates how food allergy has developed from the 1950's to the present.

The Food Allergy War

This is the story of two genuine scientific heroes. For forty years, John Bahcall and Ray Davis were engaged in a single extraordinary experiment - to find out why the Sun shines. In the end they would triumph. Davis would win the Nobel Prize and, thanks to their work, a whole new theory about how the universe is put together may have to be created.

At the heart of this story is a tiny, utterly mysterious thing called a neutrino. Trillions of them pass through your body every second, touching nothing, leaving no trace. Yet neutrinos are one of a handful of fundamental particles in the universe, essential to every atom in existence and clues to what makes the Sun work. But their ghost-like quality made trapping and understanding them immensely difficult.

What then followed was a bizarre series of experiments. They led from a vat containing 600 tons of cleaning fluid, to a vast cavern in a Japanese mountain, to a hole in the ground in Canada two kilometres deep.

What they would reveal would stun the world of science. It seems that neutrinos may be our parents. They may be the reason why everything, including us, exists.

Project Poltergeist

King Solomon's Tablet of Stone

Horizon explores the topical scientific issues investigates, the truth behind our fear of radioactivity and asks whether our nuclear nightmares really are based on reality. From Hiroshima to Chernobyl scientists have been studying the impact of exposure to radiation for over 60 years and have always assumed that any level of radiation is bad. But now some scientists are questioning the power of radiation to cause cancer and finding evidence to suggest that it may have beneficial health effects.

Nuclear Nightmares

A billion miles from home, running low on fuel, and almost out of time. After 13 years traversing the Saturn system, the spacecraft Cassini is plunging to a fiery death, becoming part of the very planet it has been exploring. As it embarks on its final assignment - a one-way trip into the heart of Saturn - Horizon celebrates the incredible achievements and discoveries of a mission that has changed the way we see the solar system.

Strange new worlds with gigantic ice geysers, hidden underground oceans that could harbour life and a brand new moon coalescing in Saturn's magnificent rings. As the world says goodbye to the great explorer Cassini, Horizon will be there for with a ringside seat for its final moments.

Goodbye Cassini - Hello Saturn

This Horizon documentary examines the Infra-Red Astronomical Satellite (IRAS) which has detected evidence of planetary systems around distant stars.

IRAS - The Supercooled Eye

In this episode, Horizon look at attempts to persuade major respected organizations to do controlled trials on a synthetic malaria vaccine.

Malaria: Battle of the Merozoites

Horizon follows five teams of scientists on the island of Mauna Kea in Hawaii as they wait for a solar eclipse.

The Black Sun

The world's oceans claim on average one ship a week, often in mysterious circumstances. With little evidence to go on, investigators usually point at human error or poor maintenance but an alarming series of disappearances and near-sinkings, including world-class vessels with unblemished track records, has prompted the search for a more sinister cause and renewed belief in a maritime myth: the wall of water. Waves the height of an office block. Waves twice as large as any that ships are designed to ride over.

These are not tsunamis or tidal waves, but huge breaking walls of water that come out of the blue. Suspicions these were fact not fiction were roused in 1978, by the cargo ship München. She was a state-of-the-art cargo ship. The December storms predicted when she set out to cross the Atlantic did not concern her German crew. The voyage was perfectly routine until at 3am on 12 December she sent out a garbled mayday message from the mid-Atlantic. Rescue attempts began immediately with over a hundred ships combing the ocean.

Freak Wave

Horizon explores an experimental medical school in Israel where students are trained primarily to care for people.

The Beersheva Experiment

The story of Einstein's most famous equation E=mc² – its role in the creation of the atom bomb and our understanding of the beginnings of the Universe.

Horizon brings you the second part of a two-part series on Albert Einsten. In the summer of 1939 Albert Einstein was on holiday in a small resort town on the tip of Long Island. His peaceful summer, however, was about to be shattered by a visit from an old friend and colleague from his years in Berlin. The visitor was the physicist Leo Szilard. He had come to tell Einstein that he feared the Nazis could soon be in possession of a terrible new weapon and that something had to be done.

Einstein's Equation of Life and Death

The controversial science of epigenetics suggests you may inherit a lot more than you imagine from your forebears.

The scientists who believe your genes are shaped in part by your ancestors' life experiences.

The Ghost in Your Genes

What makes ordinary people commit extreme acts of violence? Michael Portillo investigates the dark side of human nature, and discovers what it is like to inflict pain.

How Violent Are You?

Surgeon Gabriel Weston discovers the surprising truth about why so many people are piling on the pounds, and how to fight the fat epidemic. She discovers the hidden battles of hormones that control people's appetites, and sees the latest surgery that fundamentally changes what a patient wants to eat by altering how their brains work. Gabriel is shocked to find out that when it comes to being overweight, it is not always your fault you are fat.

The Truth about Fat

Examines the prospects for Japanese economic supremacy in the 1990s and asks whether Japan will be able to compete in the development of new technologies or whether it will continue to look to the West for technological innovation. Also considers whether the Japanese education system stifles creativity.

The Future - Made in Japan?

Horizon investigates the life for various civilizations along the river Waveney in east Angola.

Reflections on a River

Horizon presents a documentary on scientists who take themselves to Antarctica in 1980 to act as physical and mental guinea pigs.

Bitter Cold

Conjoined twins are among the rarest of human beings. There are probably fewer than a dozen adult pairs living in the world today. Only a few hundred pairs of conjoined twins are born in the whole world each year - they appear about once in every 100,000 births - but more than half of them are stillborn, and one in three live for only a few days.

Of those who survive, a very small number will be selected for separation surgery. But as there are few hospitals with the skills and experience to perform this kind of surgery, separation is still a very unusual event. The harrowing decisions which surgeons have to make when faced with conjoined twins have been highlighted by the recent case in Manchester, England. Separating conjoined twins is not only technically challenging; it can involves life and death decisions about whether one twin should be sacrificed in the hope of saving the other. But "sacrifice surgery" has a poor record of success, and the Manchester case is the latest round in an international debate about the value of separation operations.

The confidence of the surgeons, who believe that separation is essential, is challenged by medical historian, Dr Alice Dreger of Michigan State University. She argues that twins themselves might take a different view - if they were ever given a chance to express it.

Horizon interviews two pairs of adult conjoined twins - Lori and Reba Schappell in Pennsylvania and Masha and Dasha Krivoshlyapova in Moscow. Lori and Reba are joined at the head; Masha and Dasha are joined in their lower body. They say that they prefer their conjoined lives, despite the problems and challenges, rather than face the risks of separation surgery.

Lori and Reba live independent lives in their own apartment in Pennsylvania; Lori enjoys working with computers and Reba is developing a career as a country singer. Masha and Dasha had a difficult childhood; they were subjected to medical experimentation when they were very young and hidden away from the public. Since the end of the communist era they have been able to tell their story. Their autobiography is being written by a British journalist, Juliet Butler.

Horizon also follows surgeons at the Red Cross Children's Hospital in Cape Town, Africa as they plan to separate eight month old twins, Stella and Esther Alphonce. The baby girls are joined at the hip, and the surgeons have little doubt that they can and should be separated, even though the operation carries risks of disability for the twins. Historically conjoined twins who were not, or could not be separated have lived successful lives, even if this involved putting themselves on public display. The original Siamese twins, Chang and Eng Bunker, were joined by a narrow strip of flesh and could easily be separated today.

Like Millie and Christine McCoy, who also lived in the USA in the middle of the last century, they earned fame and fortune touring the world. But life for conjoined twins has never been easy, Millie and Christine were kidnapped and sold several times in their childhood. The British conjoined twin sisters, Violet and Daisy Hilton, provoked a scandal in the USA when one of them tried to get married. They did eventually marry, but they were never separated. The tragedy for conjoined twins who spend their lives together is that they inevitably die together too. When one twin dies, the heart of the other twin keeps pumping until he or she is drained of blood.

Is this another reason why twins should be separated when they are young? There are no simple answers, because every pair of twins is unique.

Conjoined Twins

Doctors Panayiotis Zavos and Severino Antinori claim they are ready to embark on the greatest human experiment of our age. They say they will attempt to clone a human being before the year is out. Most people think the objections to this are ethical - human cloning would create many moral dilemmas.

There is another question that few ever ask: is the science actually ready yet for cloning healthy humans? Horizon follows the latest research, which has led many scientists to believe that Zavos and Antinori's plans to clone the first human could end in tragedy. The programme also meets couples like Matthew and Desiree Racquer who think cloning offers them the only way to raise a child who is truly their own.

For decades, cloning remained within the realms of science fiction. The idea that instead of combining a sperm and an egg, a new human could be made from a single cell taken from an adult, seemed completely absurd. But that all changed in February 1997, when the Roslin Institute introduced the world to Dolly the sheep - the first animal cloned from an adult. Ever since Dolly, scientists have been continuing to experiment with cloning animals. So far, they have succeeded in cloning sheep, cattle, pigs, goats and mice, fuelling the belief that humans could be next.

But even Dolly's creator, Professor Ian Wilmut, is concerned that beneath the veneer of success lies a disturbing reality. Most cloning attempts on animals so far have resulted in failed implantation or abnormal foetuses. Of the animals born alive, some soon die of catastrophic organ failure. Others appear to be healthy for weeks or even months, then die suddenly, sometimes from bizarre new illnesses which do not occur in nature.

Years of painstaking work are only now revealing some vital clues to what is going wrong. Horizon talks to the scientists who have uncovered new evidence, suggesting that the process of cloning itself causes subtle errors in the way genes function. These random errors may be like a time bomb inside every clone, causing some of the strange - often fatal - problems. There's no reason to think cloned human babies would fare any better. According to embryologist Dr Susan Avery, death might be the best outcome for many human clones. If they survived, they would suffer from catastrophic illnesses that modern medicine is powerless to prevent or cure.

Dr Zavos claims that these problems are the result of the still unsophisticated methods being used by animal researchers. Using advanced in vitro fertilisation ('test tube baby') techniques, he claims that he will strive to make human cloning safer than natural reproduction. Now though, it seems that some IVF procedures themselves are being investigated for possible harmful effects on the long term health of children. Professor Gerald Schatten of the University of Pittsburgh reveals evidence of these risks, which could be magnified in cloning.

Most reproductive specialists believe that the danger to any human born by cloning is enormous. But the would-be human cloners are determined to clone a human baby. If they proceed, they may be courting tragedy.

Cloning the First Human

The magnificent ancient city of pyramids at Caral in Peru hit the headlines in 2001. The site is a thousand years older than the earliest known civilisation in the Americas and, at 2,627 BC, is as old as the pyramids of Egypt. Many now believe it is the fabled missing link of archaeology - a 'mother city'. If so, then these extraordinary findings could finally answer one of the great questions of archaeology: why did humans become civilised?  For over a century, archaeologists have been searching for what they call a mother city. Civilisation began in only six areas of the world: Egypt, Mesopotamia, India, China, Peru and Central America. In each of these regions people moved from small family units to build cities of thousands of people. They crossed the historic divide, one of the great moments in human history. Why? To find the answer archaeologists needed to find a mother city - the first stage of city-building.  They couldn't find one anywhere. Everywhere this first stage seemed destroyed or built over. And so, instead, scientists developed a number of theories. Some said it was because of the development of trade, others that it was irrigation. Some even today believe it was all because of aliens. Gradually an uneasy consensus emerged. The key force common to all civilisations was warfare.  The theory was that only the fear of war could motivate people to give up the simple life and form complex societies. To prove it, archaeologists still had to find a city from that very first stage of civilisation. If it showed signs of warfare, then the theory had to be true.  When archaeologist Ruth Shady discovered her 5,000 year old city of pyramids in the Peruvian desert, all eyes were on the New World. Ruth's extraordinary city, known as Caral, is so much older than anything else in South America that it is a clear candidate to be the mother city. It also is in pristine condition. Nothing has been built on it at all. Instead laid out before the world is an elaborate complex of pyramids, temples, an amphitheatre and ordinary houses.  Crucially, there is not the faintest trace of warfare at Caral; no battlements, no weapons, no mutilated bodies. Instead, Ruth's findings suggest it was a gentle society, built on commerce and pleasure. In one of the pyramids they uncovered beautiful flutes made from condor and pelican bones. They have also found evidence of a culture that took drugs and perhaps aphrodisiacs. Most stunning of all, they have found the remains of a baby, lovingly wrapped and buried with a precious necklace made of stone beads.

The Lost Pyramids of Caral

An investigation into the scientific approach to sporting success, as demonstrated by the former East Germany and latterly Australia. British children are already in training for the London Olympics and the programme looks at what it takes to produce a successful modern Olympian.

Winning Gold in 2012

Danny Wallace really wants a robot. He wants it to walk like him and talk like him. It's what scientists have been promising us for generations but it's a promise so far unfulfilled. Danny circumnavigates the globe searching for robot nirvana, trying to uncover how far away his dream is.

He discovers that the robotics world is as weird as it is insanely complicated. During his quest he meets a Japanese man who makes copies of himself and his daughter, an Italian who claims he's found the key to human intelligence in a video game and a Singaporean whose unpromising-looking homage to Dusty Bin might just turn out to be the robot of Danny's dreams.

Where's My Robot?

Professor Brian Cox takes a global journey in search of the energy source of the future. Called nuclear fusion, it is the process that fuels the sun and every other star in the universe. Yet despite over five decades of effort, scientists have been unable to get even a single watt of fusion electricity onto the grid.

Brian returns to Horizon to find out why. Granted extraordinary access to the biggest and most ambitious fusion experiments on the planet, Brian travels to the USA to see a high security fusion bomb testing facility in action and is given a tour of the world's most powerful laser. In South Korea, he clambers inside the reaction chamber of K-Star, the world's first super-cooled, super-conducting fusion reactor where the fate of future fusion research will be decided.

Can We Make a Star on Earth?

By our third year, most of us will have learned to count. Once we know how, it seems as if there would be nothing to stop us counting forever. But, while infinity might seem like an perfectly innocent idea, keep counting and you enter a paradoxical world where nothing is as it seems.

Mathematicians have discovered there are infinitely many infinities, each one infinitely bigger than the last. And if the universe goes on forever, the consequences are even more bizarre. In an infinite universe, there are infinitely many copies of the Earth and infinitely many copies of you. Older than time, bigger than the universe and stranger than fiction. This is the story of infinity.

To Infinity and Beyond

Iain Stewart investigates a new and controversial energy rush for the natural gas found deep underground. Sometimes, this is right under the places people live in. Getting it out of the ground involves hydraulic fracturing - or fracking.

Iain travels to America to find to find out what it is, why it is a potential game changer and what we can learn from the US experience. He meets some of the people who have become rich from fracking as well as the communities worried about the risks.

Fracking: The New Energy Rush

Liz Bonnin presents a controversial and provocative episode of Horizon, investigating how new scientific research is raising hard questions about zoos - the film explores how and why zoos keep animals, and whether they need to change to keep up with modern science or ultimately be consigned to history.

Should zoos cull their animals to manage populations? Liz travels to Copenhagen Zoo, who killed a giraffe and fed it to the lions, to witness their culling process first hand. They think it is a natural part of zoo keeping that is often swept under the carpet. Should some animals never be kept in captivity? In a world exclusive, Liz visits SeaWorld in Florida and asks if captivity drove one of their orcas to kill his trainer.

But could zoos be the answer to conserving endangered species? Liz examines their record, from helping breed pandas for the wild to efforts to save the rhinos. She meets one of the last surviving northern white rhinos and discovers the future of this species now lies in a multimillion-dollar programme to engineer them from stem cells. Veteran conservation scientist Dr Sarah Bexell tells Liz the science of captive breeding is giving humanity false hope.

Should We Close Our Zoos?

We love talking about the weather - is it too hot or too cold, too wet or too windy? It's a national obsession. Now scientists have started looking to the heavens and wondering what the weather might be like on other planets. Today, we are witnessing the birth of extra-terrestrial meteorology, as technology is allowing astronomers to study other planets like never before. They began with our solar system, sending spacecraft to explore its furthest reaches, and now the latest telescopes are enabling astronomers to study planets beyond our solar system. Our exploration of the universe is revealing alien worlds with weather stranger than anyone could ever have imagined - we've discovered gigantic storm systems that can encircle entire planets, supersonic winds, extreme temperatures and bizarre forms of rain. On some planets, the temperatures are so hot that the clouds and rain are believed to be made of liquid lava droplets, and on other planets it is thought to rain precious stones like diamonds and rubies. We thought we had extreme weather on Earth, but it turns out that it is nothing compared to what's out there. The search for the weirdest weather in the universe is only just beginning.

The Wildest Weather in the Universe

This episode of Horizon reports on how the Crab Nebula was discovered, and continuing observation of the space encounter.

The Crab Nebula

This story by Horizon reconstructs the true life story of Joey Deacon.

Joey

Horizon examines how observations of supernova in distant parts of the universe has provided evidence of the accelerating expansion of the universe. This new evidence suggests the existence of a new type energy in space which may have significant implications for the ultimate fate of the universe.

From Here to Infinity

Horizon presents the extraordinary story of a beautiful mathematical formula that changed the world, the financial markets, and indeed capitalism itself. It could do the unthinkable - it took the risk out of playing the money-markets. To its inventors it brought the Nobel Prize for economics. To those who used it, it brought great wealth. But this glittering tale would end in tragedy.

The Midas Formula

It sometimes seems as if our planet has no secrets left - but deep beneath the great Antarctic ice sheet scientists have made an astonishing discovery. They’ve found one of the largest lakes in the world. It’s very existence defies belief. Scientists are desperate to get into the lake because its extreme environment may be home to unique flora and fauna, never seen before, and NASA are excited by what it could teach us about extraterrestrial life. But 4 kilometres of ice stand between the lake and the surface, and breaking this seal without contaminating the most pristine body of water on the planet is possibly one of the greatest challenges science faces in the 21st century.

The Lost World of Lake Vostok

Everything you're about to read here seems impossible and insane, beyond science fiction. Yet it's all true.

Scientists now believe there may really be a parallel universe - in fact, there may be an infinite number of parallel universes, and we just happen to live in one of them. These other universes contain space, time and strange forms of exotic matter. Some of them may even contain you, in a slightly different form. Astonishingly, scientists believe that these parallel universes exist less than one millimetre away from us. In fact, our gravity is just a weak signal leaking out of another universe into ours.

For years parallel universes were a staple of the Twilight Zone. Science fiction writers loved to speculate on the possible other universes which might exist. In one, they said, Elvis Presley might still be alive or in another the British Empire might still be going strong. Serious scientists dismissed all this speculation as absurd. But now it seems the speculation wasn't absurd enough. Parallel universes really do exist and they are much stranger than even the science fiction writers dared to imagine.  It all started when superstring theory, hyperspace and dark matter made physicists realise that the three dimensions we thought described the Universe weren't enough. There are actually 11 dimensions. By the time they had finished they'd come to the conclusion that our Universe is just one bubble among an infinite number of membranous bubbles which ripple as they wobble through the eleventh dimension.

Now imagine what might happen if two such bubble universes touched. Neil Turok from Cambridge, Burt Ovrut from the University of Pennsylvania and Paul Steinhardt from Princeton believe that has happened. The result? A very big bang indeed and a new universe was born - our Universe. The idea has shocked the scientific community; it turns the conventional Big Bang theory on its head. It may well be that the Big Bang wasn't really the beginning of everything after all. Time and space all existed before it. In fact Big Bangs may happen all the time.

Of course this extraordinary story about the origin of our Universe has one alarming implication. If a collision started our Universe, could it happen again? Anything is possible in this extra-dimensional cosmos. Perhaps out there in space there is another universe heading directly towards us - it may only be a matter of time before we collide.

Parallel Universes

250 million years ago, long before dinosaurs roamed the Earth, the land and oceans teemed with life. This was the Permian, a golden era of biodiversity that was about to come to a crashing end. Within just a few thousand years, 95% of the lifeforms on the planet would be wiped out, in the biggest mass extinction Earth has ever known. What natural disaster could kill on such a massive scale? It is only in recent years that evidence has begun to emerge from rocks in Antarctica, Siberia and Greenland.

The demise of the dinosaurs, 65 million years ago (at the so-called K/T boundary), was as nothing compared to the Permian mass extinction. The K/T event killed off 60% of life on Earth; the Permian event 95%. Geological data to explain the destruction have been hard to find, simply because the rocks are so old and therefore subject to all kinds of erosion processes. It seems plausible that some kind of catastrophic environmental change must have made life untenable across vast swathes of the planet.

In the early 1990s, the hunt for evidence headed for a region of Siberia known as the Traps. Today it's a sub-Arctic wilderness but 250 million years ago, over 200,000km² of it was a blazing torrent of lava. The Siberian Traps were experiencing a 'flood basalt eruption', the biggest volcanic effect on Earth. Instead of isolated volcanoes spewing out lava, the crust split and curtains of lava were released. And the Siberian flood eruption lasted for millions of years. Could volcanic activity over such a long time alter the climate enough to kill off 95% of life on Earth?

The Day the Earth Nearly Died

A dirty bomb is a radiological weapon but unlike a nuclear bomb, its purpose is to contaminate rather than destroy. It uses normal explosives to disperse radioactive materials in the local environment, creating a hazard to health that could last for years unless cleaned up.

The relative ease of making such a bomb means it is a potent terrorist weapon but Horizon's investigation shows that the risk to health from most such devices need not be great. It also underlines the need for governments to act to secure radioactive sources from falling into criminal hands. Horizon deliberately avoids outlining the production process in any detail.

Horizon publishes the results of specially commissioned research, modelling two possible dirty bomb scenarios: attacks on either London or Washington DC. The main conclusion is that the health risks from a dirty bomb explosion are localised to people who are close to the incident or are in contact with the contamination. Although the modelled attack scenarios could have wide-ranging economic repercussions, the majority of the population of either capital city would have only a negligible increase in their risk of developing cancer.

Dirty Bomb

Is Wednesday red? Take part in our experiment to test whether your senses overlap.

Do melodies have a colour? Take part in our experiment to test whether you hear colours.

Imagine if every time you saw someone called Derek you got a strong taste of earwax in your mouth. It happens to James Wannerton, who runs a pub. Derek is one of his regulars. Another regular's name gives him the taste of wet nappies. For some puzzling reason, James's sense of sound and taste are intermingled.

Dorothy Latham sees words as colours. Whenever she reads a black and white text, she sees each letter tinged in the shade of her own multi-coloured alphabet - even though she knows the reality of the text is black and white. Spoken words have an even stranger effect. She sees them, spelled out letter by letter, on a colourful ticker tape in front of her head.

Both James and Dorothy have a mysterious condition called synaesthesia, in which their senses have become linked. For years scientists dismissed it, putting it in the same category as séances and spoon-bending. But now, synaesthesia is sparking a revolution in our understanding of the human mind.

Two synaesthetes seldom agree on the colours or tastes they experience. While Covent Garden may taste of crinkly chocolate to James, it's very unlikely to have the same taste for another synaesthete. And Dorothy's brother Peter, also a synaesthete, won't see M or Z in the same colour as she does. But despite these differences, scientists are now beginning to discover more and more overarching synaesthetic patterns.

Dorothy doesn't only see letters and numbers in colour. Music produces a riot of colour, too. As Dorothy hears notes going from low to high, her colours change from black and purple to mid-browns and then yellows and whites. Overall, lower notes evoke darker colours and higher notes brighter colours - and this pattern is true for most synaesthetes.

But surprisingly, when non-synaesthetes are asked to match colours and music, they show a similar pattern. Most of us seem to associate low notes with darker colours and high notes with brighter colours.

The evidence of the synaesthete in all of us doesn't end here. Another clue comes from the way we manipulate numbers. More than half of all synaesthetes who see coloured numbers also experience their numbers arranged in space around them. Heather Birt is such a synaesthete, and she's followed by a stream of numbers wherever she goes.

Recently, scientists started to investigate how non-synaesthetes deal with numbers. They found they're better at manipulating small numbers with their left hand, and their bigger numbers with our right hand. This suggests that we all somehow think of numbers as arranged in space, even if we're not aware of it. More evidence, it seems, that we're all synaesthetic to some degree. It's just that some people experience a more exaggerated version.

A few scientists believe that synaesthesia might even explain how we evolved two of the traits that define our species and have transformed our world - creativity and language.

Many famous artists have been synaesthetes - the jazz legend Miles Davis, for instance, and the painter Kandinsky. In fact, a number of studies suggest that synaesthesia may be more common among artists, poets and musicians. This has led some scientists to argue that synaesthesia and creativity may share a similar basis - that both may be down to brain processes that involve linking two seemingly unrelated areas.

Some believe that our common synaesthetic abilities may also have been the springboard to language. Connections between our senses of hearing and vision, for example, could have been an important initial step towards the creation of words. Our earliest ancestors may have first started to talk by using sounds that actually evoked the object they wished to describe. According to this theory, language could have emerged from the multitude of synaesthetic connections within our brains.

Derek Tastes of Earwax

The unpredictable results of the Theory of Relativity.

Horizon brings you the second part of a two-part series on Albert Einsten. In the summer of 1939 Albert Einstein was on holiday in a small resort town on the tip of Long Island. His peaceful summer, however, was about to be shattered by a visit from an old friend and colleague from his years in Berlin. The visitor was the physicist Leo Szilard. He had come to tell Einstein that he feared the Nazis could soon be in possession of a terrible new weapon and that something had to be done.

Einstein's Unfinished Symphony

On 7 July 2005 Britain experienced its first ever suicide attack. Four bombs exploded in central London, killing 52 people and injuring over 700. When Scotland Yard launched one of the biggest investigations in its history, another first was quickly uncovered: the suicide bombers were home-grown, they were young British men, attacking their own country. Horizon explores what makes someone want to blow themselves – and others - up?

The 7/7 Bombers: A Psychological Investigation

In 2005, Isabelle Dinoire become the first person to receive a new face. The decision made by French surgeons to perform the operation went against the findings of almost every other ethical committee in the world and has since sparked a fierce debate over the ethics of the operation. In the UK, a team led by Peter Butler struggles to get approval to perform the first full face transplant. Do the risks outweigh the benefits? Are face transplants really in the best interest of the patient? Horizon investigates.

The Worlds First Face Transplant

When disaster strikes who lives and who dies is not purely a matter of luck. In every disaster, from those people face once in a lifetime, to those they face every day, there are things that can be done to increase the chances of getting out alive.

Horizon has gathered a team of leading experts to produce the ultimate guide to disaster survival. Through controversial experiments, computer simulations and analysis of hundreds of survivor testimonies from plane crashes to ferry disasters and even 9/11, they will reveal what happens in the mind in the moment of crisis and how the human brain can be programmed for survival.

How to Survive a Disaster

Black holes are one of the most destructive forces in the universe, capable of tearing a planet apart and swallowing an entire star. Yet scientists now believe they could hold the key to answering the ultimate question - what was there before the Big Bang? The trouble is that researching them is next to impossible. Black holes are by definition invisible and there's no scientific theory able to explain them. Despite these obvious obstacles, Horizon meets the astronomers attempting to image a black hole for the very first time and the theoretical physicists getting ever closer to unlocking their mysteries. It's a story that takes us into the heart of a black hole and to the very edge of what we think we know about the universe.

Who's Afraid of a Big Black Hole?

They are the biggest questions that science can possibly ask: where did everything in our universe come from? How did it all begin? For nearly a hundred years, we thought we had the answer: a big bang some 14 billion years ago. But now some scientists believe that was not really the beginning. Our universe may have had a life before this violent moment of creation. Horizon takes the ultimate trip into the unknown, to explore a dizzying world of cosmic bounces, rips and multiple universes, and finds out what happened before the big bang.

What Happened Before the Big Bang?

Around the world, a new generation of astronomers are hunting for the most mysterious objects in the universe. Young stars, black holes, even other forms of life. They have created a dazzling new set of super-telescopes that promise to rewrite the story of the heavens. This film follows the men and women who are pushing the limits of science and engineering in some of the most extreme environments on earth. But most striking of all, no-one really knows what they will find out there.

Seeing Stars

This summer, the black hole at the centre of the Milky Way is getting ready to feast.

A gas cloud three times the size of our planet has strayed within the gravitational reach of our nearest supermassive black hole. And across the globe, telescopes are being trained on the heart of our Milky Way galaxy, some 27,000 light years from Earth, in the expectation of observing this unique cosmic spectacle.

For cosmic detectives across the Earth, it is a unique opportunity. For the first time in the history of science, they hope to observe in action the awesome spectacle of a feeding supermassive black hole.

Swallowed by a Black Hole

Homoeopathy was pioneered over 200 years ago. Practitioners and patients are convinced it has the power to heal. Today, some of the most famous and influential people in the world, including pop stars, politicians, footballers and even Prince Charles, all use homoeopathic remedies. Yet according to traditional science, they are wasting their money.

Sceptic James Randi is so convinced that homoeopathy will not work, that he has offered $1m to anyone who can provide convincing evidence of its effects. For the first time in the programme's history, Horizon conducts its own scientific experiment, to try and win his money. If they succeed, they will not only be $1m richer - they will also force scientists to rethink some of their fundamental beliefs.

The basic principle of homoeopathy is that like cures like: that an ailment can be cured by small quantities of substances which produce the same symptoms. For example, it is believed that onions, which produce streaming, itchy eyes, can be used to relieve the symptoms of hay fever.

Homeopathy: The Test

The coastline that protects the city of New Orleans is sinking into the ocean. Horizon explores what can be done to save the city if it is worth saving at all.

The Lost City of New Orleans

Horizon asks some of the biggest names in science to have a quiet word with the new American president. The United States president is quite simply the most powerful man on earth, but past presidents have often known little about science. That is a problem when the decisions they make will affect every one of us, from nuclear proliferation to climate change.

To help the new president get to grips with this intimidating responsibility, some of the world's leading scientists, from Dawkins to Watson, share some crucial words of advice.

The President's Guide to Science

Naturalist Sir David Attenborough investigates whether the world faces a population crisis and if it is the duty of individuals to change the way they live.

How Many People Can Live on Planet Earth?

There's something very odd going on in space -  something that shouldn't be possible. It is as though vast swathes of the universe are being hoovered up by a vast and unseen celestial vacuum cleaner.  Sasha Kaslinsky, the scientist who discovered the phenomenon, is understandably nervous: 'It left us quite unsettled and jittery' he says, 'because this is not something we planned to find'. The accidental discovery of what is ominously being called 'dark flow' not only has implications for the destinies of large numbers of galaxies - it also means that large numbers of scientists might have to find a new way of understanding the universe.  Dark flow is the latest in a long line of phenomena that have threatened to rewrite the textbooks. Does it herald a new era of understanding, or does it simply mean that everything we know about the universe is wrong?

Is Everything We Know About the Universe Wrong?

A decade ago, scientists announced that they had produced the first draft of the human genome, the 3.6 billion letters of our genetic code. It was seen as one of the greatest scientific achievements of our age, a breakthrough that would usher in a new age of medicine. A decade later, Horizon finds out how close we are to developing the life-changing treatments that were hoped for.

Miracle Cure? A Decade of the Human Genome

Scientists are expecting a fit of violent activity on the sun which will propel billions of tonnes of superheated gas and pulses of energy towards our planet. They have the power to close down our modern technological civilization. Horizon meets the space weathermen who are trying to predict what's coming our way, and organistions like the National Grid which are preparing for the impending solar storms.

Solar Storms: The Threat to Planet Earth

How bad can our drinking pattern be for our health? Doctors and genetically identical twins Chris and Xand van Tulleken want to find out. With the current drinking guidelines under review, the twins embark on self-experimentation to see the effects of different drinking patterns on their health. With Chris drinking 21 units spread evenly across the week and Xand having his 21 in single weekly binges, how will their bodies differ after a month? Catching up with the latest research into alcohol drinking patterns, we ask if moderate drinking is genuinely good for us - and whether binge drinking is really that bad.

Is Binge Drinking Really That Bad?

Investigating the story of how a Russian internet millionaire, Dmitry Itskov, is turning to cutting edge science to try to unlock the secret of living forever. The programme investigates the real science inspiring his bold plan to upload the human mind to a computer, and examines whether his goal of bringing about immortality for humans within thirty years is attainable.

The Immortalist

The rarely seen journey back to recovery of Richard Gray after a life-changing catastrophic stroke. Initially bed bound and unable to do anything, including speak, the initial outlook was bleak, yet occasionally small glimmers of hope emerged. Armed always with her camera, his film-maker wife Fiona captures the moment Richard moves his fingers for the first time, and then over months she documents his struggle to relearn how to walk again.

My Amazing Brain: Richard's War

'To send a spacecraft there is a little bit insane,' says Scott Bolton when talking about Jupiter, the largest planet in the solar system. But that is exactly what he has done, because Scott is head of Juno, the Nasa mission designed to peer through Jupiter's swirling clouds and reveal the wonders within. But this is no ordinary world. This documentary, narrated by Toby Jones, journeys with the scientists into the heart of a giant. Professor Kaitlin Kratter shows us how extreme Jupiter is. She has come to a quarry to measure out each planet's mass with rocks, starting with the smallest. Mercury is a single kilogram, and the Earth is 17. But Jupiter is on another scale entirely. It is seven tonnes - that is two and a half times the mass of all the other planets combined. On Kaitlin's scale it is not a pile of rocks, it is the truck delivering them. With extreme size comes extreme radiation. Juno is in the most extreme environment Nasa has visited. By projecting a 70-foot-wide, life-size Juno on a Houston rooftop, Scott shows us how its fragile electronics are encased in 200kg of titanium. As Scott puts it, 'we had to build an armoured tank to go there.' The team's efforts have been worthwhile. Professor Andrew Ingersoll, Juno's space weatherman, reveals they have seen lightning inside Jupiter, perhaps a thousand times more powerful than Earth's lightning. This might be evidence for huge quantities of water inside Jupiter. Prof Ingersoll also tells us that the Great Red Spot, a vast hurricane-like storm that could swallow the Earth whole, goes down as far as they can see - 'it could go down 1,000s of kilometres'. Deeper into the planet and things get stranger still. At the National Ignition facility in northern California, Dr Marius Millot is using powerful lasers normally used for nuclear fusion for an astonishing experiment. He uses '500 times the power that is used for the entire United States at a given moment' to crush hydrogen to the pressures inside Jupiter. Under these extreme conditions, hydrogen becomes a liquid metal. Juno is finding out how much liquid metallic hydrogen is inside Jupiter, and scientists hope to better understand how this flowing metal produces the most powerful aurora in the Solar System. But what is at Jupiter's heart? In Nice, Prof Tristan Guillot explains how Juno uses gravity to map the planet's centre. This can take scientists back to the earliest days of the solar system, because Jupiter is the oldest planet and it should contain clues to its own creation. By chalking out an outline of the Jupiter, Tristan reveals there is a huge rocky core - perhaps ten times the mass of Earth. It is now thought Jupiter started as a small rocky world. But there is a surprise, because Juno's findings suggest this core might be 'fuzzy'. Tristan thinks the planet was bombarded with something akin to shooting stars. As he puts it, 'Jupiter is quite unlike we thought'.

Jupiter Revealed

Horizon presents evidence that links the drought cycle with the number of magnetically-hyperactive sunspots.

The Sunspot Mystery

Documentary on the slatemaking industry of North Wales, now a dying craft, and the people involved with it.

The Slatemakers

Horizon investigates how teenage pregnancy is now posing massive health and social problems in many societies.

The Child Mothers

This Horizon documentary is about how and why, a sheep named Dolly, became the first cloned copy of an adult mammal.

Dawn of the Clone Age

Hidden deep beneath the Earth's surface lie one of the most destructive and yet least-understood natural phenomena in the world - supervolcanoes. Only a handful exist in the world but when one erupts it will be unlike any volcano we have ever witnessed. The explosion will be heard around the world. The sky will darken, black rain will fall, and the Earth will be plunged into the equivalent of a nuclear winter.

Normal volcanoes are formed by a column of magma - molten rock - rising from deep within the Earth, erupting on the surface, and hardening in layers down the sides. This forms the familiar cone shaped mountain we associate with volcanoes. Supervolcanoes, however, begin life when magma rises from the mantle to create a boiling reservoir in the Earth's crust. This chamber increases to an enormous size, building up colossal pressure until it finally erupts.

The last supervolcano to erupt was Toba 74,000 years ago in Sumatra. Ten thousand times bigger than Mt St Helens, it created a global catastrophe dramatically affecting life on Earth. Scientists know that another one is due - they just don't know when... or where.

Yellowstone National Park: It is little known that lying underneath one of America's areas of outstanding natural beauty - Yellowstone Park - is one of the largest supervolcanoes in the world. Scientists have revealed that it has been on a regular eruption cycle of 600,000 years. The last eruption was 640,000 years ago... so the next is overdue.

And the sleeping giant is breathing: volcanologists have been tracking the movement of magma under the park and have calculated that in parts of Yellowstone the ground has risen over seventy centimetres this century. Is this just the harmless movement of lava, flowing from one part of the reservoir to another? Or does it presage something much more sinister, a pressurised build-up of molten lava?

Scientists have very few answers, but they do know that the impact of a Yellowstone eruption is terrifying to comprehend. Huge areas of the USA would be destroyed, the US economy would probably collapse, and thousands might die.

And it would devastate the planet. Climatologists now know that Toba blasted so much ash and sulphur dioxide into the stratosphere that it blocked out the sun, causing the Earth's temperature to plummet. Some geneticists now believe that this had a catastrophic effect on human life, possibly reducing the population on Earth to just a few thousand people. Mankind was pushed to the edge of extinction... and it could happen again.

Supervolcanoes

The controversial theory that for millions of years the Earth was plunged into catastrophe - entirely smothered in ice up to one kilometre thick.

Snowball Earth

Earthquakes are among the most devastating natural disasters on the planet. In the last hundred years they have claimed the lives of over one million people. Earthquakes are destructive mainly because of their unpredictable nature. It is impossible to say accurately when a quake will strike but a new theory could help save lives by preparing cities long in advance for an earthquake.

The surface of the Earth is made up of large 'tectonic' plates. These plates are in slow but constant motion. When two plates push against each other friction generates a great deal of energy. For this reason earthquakes occur most frequently on tectonic fault lines, where two plates meet. However these fault lines run for thousands of kilometres; predicting exactly where a quake will occur is nearly impossible.

In 1992, Dr Ross Stein was monitoring a large earthquake in a town in California called Landers. Three hours later, there was another quake 67km away at Great Bear. Stein believed that this was not simply an aftershock, instead he theorised the event at Landers had set off the earthquake at Big Bear. Stein believes that when an earthquake occurs the stress that has built up along the fault, is in part, transferred along the fault line. It is this energy transfer that causes other quakes to occur hours, days or months after the original.

Earthquake Storms

Rudi Affolter and Gwen Tighe have both experienced strong religious visions. He is an atheist; she a Christian. He thought he had died; she thought she had given birth to Jesus. Both have temporal lobe epilepsy.

Like other forms of epilepsy, the condition causes fitting but it is also associated with religious hallucinations. Research into why people like Rudi and Gwen saw what they did has opened up a whole field of brain science: neurotheology.

The connection between the temporal lobes of the brain and religious feeling has led one Canadian scientist to try stimulating them. (They are near your ears.) 80% of Dr Michael Persinger's experimental subjects report that an artificial magnetic field focused on those brain areas gives them a feeling of 'not being alone'. Some of them describe it as a religious sensation.

His work raises the prospect that we are programmed to believe in god, that faith is a mental ability humans have developed or been given. And temporal lobe epilepsy (TLE) could help unlock the mystery.

God On The Brain

This week Horizon investigates the science behind the Bible Code.

What he can see is truly horrific; according to Drosnin, the world could end in an atomic holocaust - in 2006.

It sounds preposterous yet Drosnin claims to have serious scientific backing. Behind his findings lies the work of one of the world's most brilliant theoretical mathematicians, an Israeli professor called Eliyahu Rips.

In 1994, using exactly the same ancient code, Michael Drosnin accurately predicted the assassination of the Israeli Prime Minister Yitzak Rabin - twelve months before it occurred.

Drosnin's books on the Bible Code have been translated into most of the world's major languages and are read by millions of people. If he's right, he's stumbled on one of the most important discoveries ever made.

The Bible Code

Pianist Nick van Bloss has Tourette's syndrome. Is his illness a blessing or a curse?

Is there really such a thing as the mad genius? Can an illness be both a blessing and a curse?

At seven years old, Nick van Bloss started shaking his head, grinding his teeth and making wild whooping noises. Nick had Tourette's syndrome. No medical intervention helped him. But one activity stopped it all...

The moment Nick placed his hands on the piano keys his symptoms vanished. By the age of 20, he was an award winning international pianist. He felt sure that his illness had made him the success he was.

But there is a catch. The brain state necessary for his genius can also be dangerously close to mental chaos. Nick's personal journey reveals how close he came to the edge and how determined he is to triumph.

Mad but Glad

Seven high-flyers are put through a series of tests to measure their intelligence

Can you think of 100 different uses for a sock? How would you cope with glasses that turn everything upside down? What's your emotional intelligence? Can you create a work of art in ten minutes?

Horizon takes seven people who are some of the highest flyers in their field - a musical prodigy, a quantum physicist, an artist, a dramatist, an RAF fighter pilot, a chess grandmaster and a Wall Street trader. Each is put through a series of tests to discover who is the most intelligent?

The principle way that we measure intelligence, the IQ test, remains popular and convenient. Yet most psychologists agree that it only tells half the story... at most. Where they disagree is how to measure intelligence, for the simple reason that the experts still don't know exactly what it is.

Battle of the Brains

Ever since he was at school, actor and comedian Alan Davies has hated maths. And like many people, he is not much good at it either. But Alan has always had a sneaking suspicion that he was missing out.

So, with the help of top mathematician Professor Marcus du Sautoy, Alan is going to embark on a maths odyssey. Together they visit the fourth dimension, cross the universe and explore the concept of infinity. Along the way, Alan does battle with some of the toughest maths questions of our age.

But did his abilities peak 25 years ago when he got his grade C O-Level? Or will Alan be able to master the most complex maths concept there is?

Alan and Marcus Go Forth and Multiply

Talking is something that is unique to humans, yet it still remains a mystery. Horizon meets the scientists beginning to unlock the secrets of speech - including a father who is filming every second of his son's first three years in order to discover how we learn to talk, the autistic savant who can speak more than 20 languages, and the first scientist to identify a gene that makes speech possible. Horizon also hears from the godfather of linguistics, Noam Chomsky, the first to suggest that our ability to talk is innate. A unique experiment shows how a new alien language can emerge in just one afternoon, in a bid to understand where language comes from and why it is the way it is.

Why Do We Talk?

Alcohol is by far the most widely used drug - and a dangerous one at that. So why are so many of us drinking over the recommended limits? Why does alcohol have such a powerful grip on us? How much of our relationship with this drug is written in our genes? What are the real dangers of our children drinking too young? Addiction expert John Marsden, who likes a drink, makes a professional and personal exploration of our relationship with alcohol. He undergoes physical and neurological examinations to determine its impact, and finds out why some people will find it much harder than others to resist alcohol. Even at the age of 14 there may be a way of determining which healthy children will turn into addicts. John experiments with a designer drug being developed that hopes to replicate all the benefits of alcohol without the dangers. Could this drug replace alcohol in the future?

Do I Drink Too Much?

Just months ago, the world stood in fear of an emerging new disease that threatened to kill millions. A new flu variant H1N1 had arrived. In the UK alone, 65,000 deaths were predicted. Yet to date, these dire warnings have not materialised. If this latest pandemic has taught anything, it is just how little is understood about the invisible world of viruses. But that has not stopped scientists trying. Horizon follows the leading researchers from across the world, who are attempting to unravel the many secrets of viruses to understand when and why they kill.

Why Do Viruses Kill?

Horizon examines the evidence that our ancestors' changing diet and mastery of fire prompted anatomical and neurological changes that took us out of the trees and into the kitchen.

Did Cooking Make Us Human?

Horizon reveals the untold story of the 87-day battle to kill the Deepwater Horizon oil blowout a mile beneath the waves - a crisis that became America's worst environmental disaster. Engineers and oil men at the heart of the operation talk for the first time about the colossal engineering challenges they faced and how they had to improvise under extreme pressure. They tell of how they used household junk, discarded steel boxes and giant underwater cutting shears to stop the oil. It's an operation that one insider likens to the rescue of Apollo 13.

Deepwater Disaster - The Untold Story

There is a strange and mysterious world that surrounds us, a world largely hidden from our senses. The quest to explain the true nature of reality is one of the great scientific detective stories. Clues have been pieced together from deep within the atom, from the event horizon of black holes, and from the far reaches of the cosmos. It may be that that we are part of a cosmic hologram, projected from the edge of the universe. Or that we exist in an infinity of parallel worlds. Your reality may never look quite the same again.

What Is Reality?

Six months after the explosions at the Fukushima nuclear plant and the release of radiation there, Professor Jim Al-Khalili sets out to discover whether nuclear power is safe. He begins in Japan, where he meets some of the tens of thousands of people who have been evacuated from the exclusion zone. He travels to an abandoned village just outside the zone to witness a nuclear clean-up operation. Jim draws on the latest scientific findings from Japan and from the previous explosion at Chernobyl to understand how dangerous the release of radiation is likely to be and what that means for our trust in nuclear power.

Fukushima: Is Nuclear Power Safe?

Plastic surgeon Dr Rozina Ali leaves the operating theatre behind for the frontiers of skin science and asks if it is possible to make your skin look younger without surgery. She discovers the latest research about how the foods we eat can protect our skin from damage, and how a chemical found in a squid's eye is at the forefront of a new sun protection cream. She also finds out how sugar in our blood can make us look older, and explores an exciting new science called glycobiology which promises a breakthrough in making us look younger.

The Truth About Looking Young

Michael Mosley has set himself a truly ambitious goal: he wants to live longer, stay younger and lose weight in the bargain. And he wants to make as few changes to his life as possible along the way. He discovers the powerful new science behind the ancient idea of fasting, and he thinks he's found a way of doing it that still allows him to enjoy his food. Michael tests out the science of fasting on himself - with life-changing results.

Eat, Fast and Live Longer

As they contain no active ingredient, placebo medicines and pills should not really work, but they are now being shown to be effective in helping treat pain and depression and even alleviating some of the symptoms of Parkinson's disease. This programme explores why they work and how everyone could benefit from them.

The Power of the Placebo

One in every 1,000 pregnancies in Britain has a spine or brain defect like spina bifida. 30 years ago, actress Ruth Madeley was one of them. Despite having spina bifida herself, it is a condition she doesn't fully understand. In this programme, Ruth sets out to discover why she has it, whether it could have been prevented and what it means for her future. Ruth meets the lord campaigning for a change in the law that he says could prevent thousands of birth defects. And she discovers that a pioneering surgery could offer a different future for babies diagnosed with spina bifida, by operating on them before they are even born. She discovers how this surgery was invented, meets the families whose lives it has changed and follows the team of British surgeons preparing to perform this extraordinary foetal surgery in the UK for the very first time. But Ruth also examines attitudes in Britain today and asks whether we should change the way we see disability.

Spina Bifida & Me

When she's diagnosed with cervical cancer at the age of 36, Hannah Fry explores the problematic issues surrounding how we screen for and treat cancer, asking if we could be overmedicalising it.

Making Sense of Cancer with Hannah Fry

In the summer of 2000, one of the great frontier cities of the Roman Empire, the city of Zeugma, all but disappeared from the face of the Earth under the flood waters of a dam. In a bid to modernise, the Turkish government has embarked on one of the most ambitious engineering projects in the world, building a series of dams on the Euphrates over the past twenty years. Almost every dam threatens ancient remains that lie below in one of the most archaeologically rich regions of the world. The completion of the Birecik dam, featured in this film, has flooded the valley where Zeugma is buried. The city on the flat plain has entirely disappeared and the waters have now risen to cover 30% of the city on the hillside.

Horizon tells the story of the archaeologists' fifth and final visit, struggling to save what they could before the dam waters rose. It witnesses the uncovering of some of the most beautiful examples of Roman art ever found. The team’s discoveries at Zeugma caused an international outcry and further excavations were hurriedly put together.

Since 1995, French archaeologists Pierre Leriche and Catherine Abadie-Reynal have taken up the challenge to save what they can from the city before the dam is finished. The archaeologists have two main tasks - to uncover the history of this desperately under-excavated region of Turkey and to remove what treasures they could from the site before they were lost forever. On this, their final excavation, they had to work against the clock: they only had a permit to dig for six weeks

Zeugma was founded by one of Alexander the Great’s generals, Seleucia Nicator, and prospered under later Roman rule. It became one of the major cities of the Roman eastern frontier with a garrison of over 6,000 soldiers. The city’s bridge across the Euphrates made it one of the most critical trading cities in the region, on the silk routes to the East. The archaeologists know that the city contains vital clues to the history of the region. Previously looted exquisite mosaics have hinted at the treasures of its past that must be buried somewhere in the vast site.

The part of the old city on the Euphrates flood plain, Apamea, was the first to go. But the archaeologists didn’t stand a chance of excavating it in such a short amount of time. So using a technology originally developed for finding oil and mineral deposits, they instead generated a picture of the buried city just as it lies below ground. They discovered a preserved ancient Greek city, laid out in a perfect grid. Meanwhile, in the remains of a Roman villa across the river, the archaeologists had an extraordinary stroke of luck.

With only five days left on the excavation permit, Catherine Abadie-Reynal unearthed a masterpiece: a beautiful Roman mosaic floor. The discovery caused an international outcry and hit the headlines across the world. The archaeologists were granted more days to excavate, but they could not stem the tide of the dam project.

With time running out, they uncovered more stunning mosaics in the villa. They were dug out from the site and sent to a local museum at Gaziantep - just in time. By mid June 2000, the newly uncovered fourteen room villa disappeared underwater. By October, the level of the water finally settled to form a vast, still lake in the valley. All excavations at the site ceased.

There's recently been a move by the Turkish government to declare Zeugma a site of special archaeological interest. The remainder of the ancient city on the hillside could, in theory, still be explored.

The dam will not only erase much of Zeugma from history. It will also displace 30,000 people, mostly Kurds, from the villages they have lived in for generations. For many, the loss of Zeugma is a tragedy.

The Secret Treasures of Zeugma

This is the story of a book that could have changed the history of the World. To the untrained eye, it is nothing more than a small and unassuming Byzantine prayer book, yet it sold at Christies for over $2m. For faintly visible beneath the prayers on its pages are other, unique, writings - words that have been lost for nearly two thousand years.

The text is the only record of work by one of the world's greatest minds - the ancient Greek, Archimedes - a mathematical genius centuries ahead of his time. Hidden for a millennium in a middle eastern library, it has been written over, broken up, painted on, cut up and re-glued. But in the nick of time scientists have saved the precious, fragile document, and for the first time it is revealing just how revolutionary Archimedes' ideas were. If it had been available to scholars during the Renaissance, we might have reached the Moon over a hundred years ago.

The trail begins in the tenth century, when a scribe made a unique copy of the most important mathematics that Archimedes ever developed. For 200 years the document survived, but the mathematics in it was so complex that no one paid it any attention. So when one day a monk was looking for some new parchment - an expensive commodity at the time - to write a new prayer book, the answer seemed obvious. He used the Archimedes manuscript. He washed the Greek text off the pages, cut them in half, rebound them, and turned the Archimedes manuscript into an everyday prayer book. As he piously wrote out his prayers, he had no idea of the genius he was obliterating.

Several hundred years later, the Renaissance was under way. Scientists were beginning to grapple with new concepts, working out how mathematics could be used to explain the World around them. Little did they know that many of the problems they were just encountering Archimedes had already solved more than a thousand years before. So, tragically, they had to do that research all over again, setting back the development of science and technology immeasurably.

Then in 1906, in Constantinople, the document mysteriously turned up in a monastic library. An opportunistic scholar called Johan Ludwig Heiberg identified the text as Archimedes' writings. Although the Greek text was very faint, Heiberg was able to decipher some of it. What he found astonished him, and made the front page of the New York Times. He revealed that Archimedes' manuscript contained something called 'The Method', which showed not only Archimedes' final proofs, but for the first time revealed the process of how he went about making his discoveries.

But then disaster struck again. World War One broke out and in its aftermath the Archimedes manuscript disappeared.

Scholars had given up any hope of seeing the manuscript again, but in the 1960s odd rumours began to surface that it was to be found in Paris. It took 30 more years, but in 1991 an expert from Christies found it in the hands of a French family. When it reached auction, it was sold to an anonymous millionaire, who has now loaned it to the Walters Art Museum in Baltimore for conservation.

Although the text is incredibly difficult to read, with state-of-the-art imaging equipment, they are gradually piecing together all of the writing for the very first time. And as the team in Baltimore peel back the glue, leather and centuries of dirt, dissolve the blue-tack and unfold the lines of Greek that are buried in the spine of the book, they are building up a picture of a man who was thousands of years ahead of his time. Not only was Archimedes coming to terms with the profound subject of infinity, he had taken the first crucial steps towards calculus, a branch of mathematics that had to be reinvented after the Renaissance, and which is today used to describe every physical phenomenon from the movement of the planets to the construction of a skyscraper. Who knows what human minds could have achieved if they had only known what Archimedes already knew?

Archimedes' Secret

On Easter Day 1722, Dutch explorers landed on Easter Island. A civilisation isolated by 4,000km of Pacific Ocean was about to meet the outside world for the first time in centuries. The strangers were about to find something very strange themselves - an island dotted with hundreds of huge stone statues and a society that was not as primitive as they expected. The first meeting was an immense clash of cultures. (Bloody too: the sailors killed ten natives within minutes of landing.) Where had the Islanders originally come from? Why and how had they built the figures? Modern science is piecing together the story, but it is far too late for the Easter Islanders themselves.

They were virtually wiped out by a series of disasters - natural and man made - that brought a population of 12,000 down to just 111 in a few centuries. The Island's inhabitants today all have Chilean roots, making solving the mysteries even harder. There is no one to ask about the first people of Easter Island. Although fragmentary legends have been passed down, only science can hope to explain the rise and fall of this unusual civilisation.

The Mystery Of Easter Island

Dr Money and the Boy with No Penis

Horizon producer David Sington on why predictions about the Earth's climate will need to be re-examined.

Global Dimming

Dr Brian Cox wants to know why the Universe is built the way it is.

Particle physicist and ex D:Ream keyboard player Dr Brian Cox wants to know why the Universe is built the way it is. He believes the answers lie in the force of gravity. But Newton thought gravity was powered by God, and even Einstein failed to completely solve it. Heading out with his film crew on a road trip across the USA, Brian fires lasers at the moon in Texas, goes mad in the desert in Arizona, encounters the bending of space and time at a maximum security military base, tries to detect ripples in our reality in the swamps of Louisiana and searches for hidden dimensions just outside Chicago.

What on Earth is Wrong With Gravity?

Why are you more likely to have a heart attack at eight o'clock in the morning or crash your car on the motorway at two o'clock in the afternoon? Can taking your medication at the right time of day really save your life? And have you ever wondered why teenagers will not get out of bed in the morning?

The answers to these questions lie in the secret world of the biological clock.

The Secret Life of Your Bodyclock

Horizon follows the emotional journey of three young people with currently untreatable conditions to see if, within their lifetime, they can be cured. Sophie Morgan is determined not to spend the rest of her life in a wheelchair. She is tempted by the online claims of unregulated private clinics promising a cure using stem cells. Anthony Bath was just 20 when his right leg was amputated after a botched pinning procedure. In Finland, Anthony witnesses one of the world's first operations in which stem cells are used to replace bone. Dean Third was diagnosed with dilated cardiomyopathy, a condition in which his damaged heart could cause his death at any moment. Desperate for a cure, he visits Dr Anthony Mathur from University College London to witness the world's first trial using stem cells taken from bone marrow.

Fix Me

Horizon tells amazing science stories, unravels mysteries and reveals worlds you've never seen before.

All Episodes of Horizon

Season 1

The World of Buckminster Fuller

Season 1 Episode 1 - Aired 2/4/1964

Strangeness Minus Three

Season 1 Episode 4 - Aired 7/25/1964

Pesticides and Posterity

Season 1 Episode 2 - Aired 5/30/1964

A Candle to Nature

Season 1 Episode 3 - Aired 6/27/1964

The Air of Science

Season 1 Episode 5 - Aired 8/22/1964

The Knowledge Explosion

Season 1 Episode 6 - Aired 9/21/1964

The Amateur Scientist

Season 1 Episode 7 - Aired 10/19/1964

Tots and Quods and Woodgeries

Season 1 Episode 8 - Aired 11/16/1964

Science, Toys and Magic

Season 1 Episode 9 - Aired 12/14/1964