The Mediterranean Sea has been dubbed the incubator of western civilization and Ancient Astronaut Theorists believe stories of giant being roaming the earth is proof of otherworldly visitors, in this clip from Season 15, "Giants of the Mediterranean." Watch all new episodes of Ancient Aliens, ...

Discover Antarctica's secret past in this compilation from Ancient Aliens. 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 Channel shows: ...

Since the discovery of exoplanets, Ancient Astronaut Theorists believe they could be home to our true ancestors. See more in this clip from "Aliens and Outer Space." Watch all new episodes of Ancient Aliens, Fridays, at 9/8c, and next day on The HISTORY Channel website at ...

Ancient Astronaut Theorists made a shocking discovery related to the Indus people from Mohenjo Daro. See more in this clip from Aliens and Lost Civilizations. Watch all new episodes of Ancient Aliens, Fridays, at 9/8c, and next day on The HISTORY Channel website at http://history.com/schedule. ...

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." #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: ...

Ancient Astronaut Theorists believe a group of airmen encountered a UFO from the future, in this clip from 18, "The Time Benders." #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: http://histv.co/SubscribeHistoryYT Find out more about the show ...

While in restricted airspace, pilots spot an unidentified object performing unusual maneuvers unlike any other military aircraft, in this clip from Season 18, "Alien Air Force." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite The HISTORY ...

Ancient Astronaut Theorists investigate a possible connection between Atlantis and Native American origin stories, in this clip from Season 18, "Secrets of the Star Ancestors." #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: ...

Ancient Astronaut Theorists come face to face with extraterrestrial writings at Rock Art Ranch, in this clip from Season 18, "Secrets of the Star Ancestors." Watch all new episodes of Ancient Aliens, Fridays at 9/8c, and stay up to date on all of your favorite The HISTORY Channel shows at ...

Ancient Astronaut Theorists believe that the long lost Ark of the Covenant contained extraterrestrial powers much too powerful for mankind, in this clip from Season 18, "Recovering the Ark of the Covenant." #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY ...

Tune in to Alien Invasion Week on History starting Monday 9/30 through Friday 10/4 for new Ancient Aliens, plus the premiere of In Search Of, new UFO Specials and More! There are geoglyphs around the world that Ancient Astronaut Theorists believe could have encoded alien messages in this clip ...

Tune in to Alien Invasion Week on History starting Monday 9/30 through Friday 10/4 for new Ancient Aliens, plus the premiere of In Search Of, new UFO Specials and More! Nikolai Tesla credited his many inventions to his ability to realize them entirely in his mind leading Ancient Astronaut ...