Considered by many to be the greatest civilization in the history of the Americas, the Maya thrived for more than 2,000 years. Now, new evidence is being discovered that completely upends our understanding of this ancient culture... and might provide evidence that the Maya came in contact with extraterrestrial visitors.

Puma Punku in Bolivia features stone blocks, each carved with precision; the blocks lie scattered across the landscape, confusing archaeologists as to what the ancient site might have been.

The Aztecs built one of the world's most powerful and feared empires and they claimed that they were guided by a pantheon of more than a thousand gods who came to Earth from different parts of the universe. Could the incredible story of their rise to power and their sudden demise, reveal a history of extraterrestrial intervention in Mesoamerica?

Deep beneath the sands of Egypt lie 24 enormous sarcophagi, and every one of them is empty; discussing what purpose those giant tombs had served.

For more than four decades, award-winning journalist Linda Moulton Howe has covered the most mysterious phenomena on Earth. Could her investigations on everything from bizarre animal deaths to crop formations and alien abductions lead us to a profound new reality?

For thousands of years, humankind has attempted to make contact with beings from beyond Earth; now, the search for extraterrestrial intelligence is ramping up, with new technologies allowing individuals to explore the universe.

In the early 1900s, a modern-day prophet from the hills of Kentucky became a worldwide sensation: Edgar Cayce. He claimed to receive visions of both the past and the future while in a trance, he healed the sick, and alleged to have encounters with otherworldly beings. Could it be that Edgar Cayce was a vessel used to carry out an alien agenda?

For decades, incredible claims have been made about an extraterrestrial presence on Earth, and the government has gone to great lengths to discredit them.

Dr. Jacques Vallée has many scientific degrees, is a best-selling author and is regarded as one of the internet's founding fathers. But he is best renowned for his groundbreaking work on the subject of UFOs, where his bold theories call into question our understanding of alien life.

The discovery of the ancient megalithic site of Karahan Tepe in southern Turkey turned the world of archaeology on its head, displaying engineering skills far beyond what the people of the time were thought to be capable of. But could new evidence reveal that this more than 11,000-year-old complex was built not by humans…but giants?

For thousands of years, cultures around the world have held a belief in stargates through which beings have traveled to Earth from distant points in the universe and even other dimensions. Could such portals truly exist? And if we obtain the key to unlocking the stargates, will we find a cosmos teaming with life?

Volcanoes have inspired countless myths and legends, but curiously, they are also major hotspots for UFO sightings; is it possible that these geological formations, which can generate great energy, are attracting otherworldly visitors?

Terrifying encounters at 40,000 feet. Pilot accounts of UFOs taking control of their aircraft. Entire jumbo jets disappearing into thin air. Since the dawn of aviation, pilots have experienced unexplainable events in the sky. Could they have witnessed aliens in our airspace?

Enormous, megalithic structures of mysterious origins. A vast underground complex containing the remains of what some believe to be otherworldly beings. Could the ancient mysteries that exist on the Mediterranean islands of Malta be connected to local legends of alien visitation–and giant hybrid beings?

More than 7,000 years ago, the ancient Sumerians established what is considered the world's first civilization and they credited their extraordinary achievements to their gods, the Anunnaki. But is it possible that these powerful beings were, in fact, extraterrestrial visitors to Earth?

Stories of god-like beings providing instruction to early humans, helping establish the first civilizations; exploring if mysterious figures who appear throughout history provide evidence that these otherworldly teachers have been here all along.

Ancient Aliens is counting down ten of the most astonishing and unexplainable technologies in history. From mysterious golden orbs discovered in Mexico, to a sacred wooden box that could communicate with the heavens and an ancient tomb that is said to depict an astronaut. Might these sensational artifacts be evidence of otherworldly contact?

At nearly 14,000 years old, the ruins of Puma Punku are the oldest and most baffling on the face of the Earth. No one knows who designed and built this complex of sophisticated inter-locking blocks, and then vanished. Researchers investigate the ruins on-location in Peru and present new computer analyses. Forensic evidence on the ground, together with local myths and legends, suggest this site may have been designed and even once inhabited by a species of extraterrestrials.

Giorgio Tsoukalos and David Childress explore the mysterious chain of manmade islets in Micronesia's Nan Madol; built from 250 million tons of volcanic rock, there are local legends that strange visitors floated the massive rocks through the air.

In this extraordinary two-hour special, Shatner will bring thought-provoking questions to the leading experts of the show. Ancient Astronaut theorists Giorgio Tsoukalos, Erich von D niken, David Childress, William Henry and Linda Moulton Howe will be joined by former British Ministry of Defense investigator Nick Pope, rocket scientist Dr. Travis Taylor, theoretical physicist Dr. Michio Kaku, and religious history experts Rabbi Ariel Bar Tzadok and Reverend Michael Carter. They will explore everything from human origins to groundbreaking archaeological finds, new understandings of the cosmos and the profound possibility that we are not alone in the universe.

Throughout the world, ancient objects have been found that leave archaeologists at a loss. Could these impossible artifacts suggest that advanced--and perhaps even extraterrestrial--civilizations existed on Earth thousands of years before our own?

Ancient Aliens is counting down the world’s top ten pyramid sites, from a valley in Peru with over 250 hidden pyramids to an ancient Greek city with mysterious 4800-year-old ruins to Egypt’s famous Giza Plateau. Could the extraordinary structures that stand at these sites provide evidence of extraterrestrial visitation?

Throughout the world there are mysterious ancient stones shaped into perfect spheres; many of them show clear evidence of being manmade and some completely defy explanation; the mystery of the stone spheres could provide clues about humankind's past.

From biblical patriarchs to modern day alien abductees, throughout history, there have been people who claimed to have contact with otherworldly beings; often bearing important messages for humanity.

Across the globe, reports of mysterious glowing orbs are on the rise. Their movements frequently defy the laws of physics and now they are even being reported near military bases, ships and nuclear weapon facilities. Do they represent a non-human intelligence and if so, why are they here?