Horizon backdrop
Documentary

The Best Episodes of Horizon

Every episode of Horizon ranked from best to worst. Let's dive into the Best Episodes of Horizon!

Binge this in 48d 19h•Peaking at 10.0/10

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

Airs on
BBC Two
BestEpisodes
WorstEpisodes
BestSeasons
AllEpisodes

Seasons61

All12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061

Episode Rankings

  1. #1 Fan Favorite
    Click to reveal
    Horizon Season 19 Episode 22 - The Mysterious Mr. Tesla
    10.0/10(1 votes)

    #1 - The Mysterious Mr. Tesla

    S19:E22

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  2. Horizon Season 49 Episode 11 - Global Weirding
    10.0/10(1 votes)

    #2 - Global Weirding

    S49:E11

    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.

    Director:David Stewart
    Writer:Unknown

    Be the first to start the conversation for this episode

  3. Horizon Season 49 Episode 13 - Defeating Cancer
    10.0/10(1 votes)

    #3 - Defeating Cancer

    S49:E13

    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.

    Directors:Naomi Law, Diana Ellis-Hill
    Writer:Unknown

    Be the first to start the conversation for this episode

  4. Horizon Season 37 Episode 15 - Valley of Life or Death
    9.6/10(12 votes)

    #4 - Valley of Life or Death

    S37:E15

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  5. Horizon Season 11 Episode 6 - The Writing on the Wall
    9.2/10(15 votes)

    #5 - The Writing on the Wall

    S11:E6

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  6. Horizon Season 52 Episode 3 - Allergies: Modern Life and Me
    9.0/10(1 votes)

    #6 - Allergies: Modern Life and Me

    S52:E3

    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?

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

    7. Trending NowTRENDING NOW

    The 20 WORST Episodes of Horizon

    READ
  7. Horizon Season 45 Episode 15 - Do You Know What Time It Is?
    8.7/10(93 votes)

    #7 - Do You Know What Time It Is?

    S45:E15

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  8. Horizon Season 18 Episode 9 - Gentlemen, Lift Your Skirts
    8.6/10(154 votes)

    #8 - Gentlemen, Lift Your Skirts

    S18:E9

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  9. Horizon Season 37 Episode 5 - Miracle In Orbit
    8.6/10(7 votes)

    #9 - Miracle In Orbit

    S37:E5

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  10. Horizon Season 37 Episode 19 - Atlantis Reborn Again
    8.6/10(29 votes)

    #10 - Atlantis Reborn Again

    S37:E19

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  11. Horizon Season 38 Episode 2 - The Missing Link
    8.5/10(10 votes)

    #11 - The Missing Link

    S38:E2

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  12. Horizon Season 21 Episode 19 - Global Village
    8.4/10(14 votes)

    #12 - Global Village

    S21:E19

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  13. Horizon Season 22 Episode 12 - The Food Allergy War
    8.4/10(15 votes)

    #13 - The Food Allergy War

    S22:E12

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  14. Horizon Season 41 Episode 9 - Project Poltergeist
    8.4/10(14 votes)

    #14 - Project Poltergeist

    S41:E9

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  15. Horizon Season 41 Episode 12 - King Solomon's Tablet of Stone
    8.4/10(17 votes)

    #15 - King Solomon's Tablet of Stone

    S41:E12

    No description available

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  16. Horizon Season 43 Episode 11 - Nuclear Nightmares
    8.4/10(20 votes)

    #16 - Nuclear Nightmares

    S43:E11

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  17. Horizon Season 54 Episode 14 - Goodbye Cassini - Hello Saturn
    8.4/10(38 votes)

    #17 - Goodbye Cassini - Hello Saturn

    S54:E14

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  18. Horizon Season 22 Episode 14 - IRAS - The Supercooled Eye
    8.3/10(58 votes)

    #18 - IRAS - The Supercooled Eye

    S22:E14

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  19. Horizon Season 29 Episode 5 - Malaria: Battle of the Merozoites
    8.3/10(33 votes)

    #19 - Malaria: Battle of the Merozoites

    S29:E5

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  20. Horizon Season 29 Episode 6 - The Black Sun
    8.3/10(24 votes)

    #20 - The Black Sun

    S29:E6

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  21. Horizon Season 39 Episode 14 - Freak Wave
    8.3/10(27 votes)

    #21 - Freak Wave

    S39:E14

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  22. Horizon Season 15 Episode 20 - The Beersheva Experiment
    8.2/10(15 votes)

    #22 - The Beersheva Experiment

    S15:E20

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

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  23. Horizon Season 42 Episode 3 - Einstein's Equation of Life and Death
    8.2/10(50 votes)

    #23 - Einstein's Equation of Life and Death

    S42:E3

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  24. Horizon Season 42 Episode 20 - The Ghost in Your Genes
    8.2/10(26 votes)

    #24 - The Ghost in Your Genes

    S42:E20

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

  25. Horizon Season 46 Episode 11 - How Violent Are You?
    8.2/10(18 votes)

    #25 - How Violent Are You?

    S46:E11

    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.

    Director:Unknown
    Writer:Unknown

    Be the first to start the conversation for this episode

Best Episodes Summary

"The Mysterious Mr. Tesla" is the best rated episode of "Horizon". It scored 10/10 based on 1 votes. Directed by Unknown and written by Unknown, it aired on 12/20/1982. This episode scored 0.0 points higher than the second highest rated, "Global Weirding".