One of the most compelling arguments for the Ancient Astronaut theory is the remarkable engineering evident in the construction of ancient megalithic sites worldwide. See more in this scene from Season 1, Episode 1, "Extraordinary Engineering." Watch all new episodes of Ancient Aliens, Fridays ...

Is it possible that ancient rulers were, in fact, connected with divine or, some would say, extraterrestrial forces? And, if so, what was their purpose? On every continent there are stories of incredible treasures that have been lost for centuries. See more in Season 2, Episode 10, "Ancient ...

Ancient Astronaut Theorists question who built Nan Madol after an artificial irrigation system is discovered, in this clip from Season 15, "The Mystery of Nan Madol." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY ...

Ancient Astronaut Theorists visit the most sacred temple in Egypt, The Temple of Edfu, in this clip from Season 18, "Ancient Aliens On Location: Decoding The Alien Glyphs." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The ...

For thousands of years, pyramids were the largest structures on Earth. But what purpose did the pyramids serve? See more in this marathon from Ancient Aliens. Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY Channel ...

The Ark of the Covenant is one of the most sought after religious relics of all times and far more than just a box that contained the Ten Commandments. See more in Season 6, Episode 10, "Aliens and the Lost Ark." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on ...

Explore the ancient ruins of Teotihuacán in this Ancient Aliens compilation. Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for more from ...

Across ancient civilizations, the world's mountains were viewed as the sacred home to all-powerful gods. See more in Season 6, Episode 11, "Aliens and Mysterious Mountains." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The ...

These ancient structures hold not only history but deep secrets that will soon be revealed. See more in this Ancient Aliens compilation. Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY Channel website at ...

Check out these insane moments in this Ancient Aliens compilation. Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for more from Ancient ...

Did aliens help us out in the war?! See more in this scene from Season 1, Episode 2, "Ancient Close Encounters." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY Channel website at http://history.com/schedule. ...

More than 10,000 crop circles have been reported worldwide, on nearly every continent on earth. See more in Season 1, Episode 17, "Circles, Rituals and Shamans." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite shows on The HISTORY Channel ...