Could there really be hidden extraterrestrial bases at these landmarks? See more in this compilation from Season 20, Episode 3, "The Top Ten Hidden Alien Bases." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens ...

Could there be evidence to the atomic bomb actually existing thousands of years ago? See more in this scene from Season 2, Episode 8, "Aliens and Mysterious Texts." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens ...

Are extraterrestrials responsible for this architectural knowledge? See more in this scene from Season 2, Episode 8, "Aliens and Mysterious Texts." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for more ...

Could extraterrestrials be keeping an eye on America? Find out in this Ancient Aliens compilation! Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY ...

Could this layer of ash found beneath the Earth's soil be evidence of a major global event? See more in this scene from Season 2, Episode 8, "Aliens and Mysterious Texts." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. ...

Prominent world leaders including the British Royal Family, Japan's Defense Minister, the Chinese government, and Russia's former president have allegedly been investigating Unidentified Aerial Phenomena (UAPs) for years. Learn more in this scene from Season 2, Episode 9, "Aliens and World ...

The French government releases information regarding Unidentified Aerial Phenomena to the public. See more in this scene from Season 2, Episode 9, "Aliens and World Leaders." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. ...

Unidentified air conditions in China shock civilians and government officials alike. See more in this scene from Season 2, Episode 9, "Aliens and World Leaders." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens ...

Prominent world leaders including the British Royal Family, Japan's Defense Minister, the Chinese government, and Russia's former president have allegedly been investigating Unidentified Aerial Phenomena (UAPs) for years. See more in this scene from Season 2, Episode 9, "Aliens and World ...

According to Francis Crick, human DNA was far too complex to have evolved over the history of planet earth, which led to theories of extraterrestrial interference with human DNA, in this clip from Season 17, "The Human Experiment." #AncientAliens Subscribe for more from Ancient Aliens and ...

Across the globe, monumental stone figures silently bear witness to a forgotten era. See more in this scene from Season 2, Episode 10, "Alien Effigies." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for ...

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. See more in this scene from Season 20, Episode 7, "Secrets of the Sumerians." Watch your favorite ...