Ancient Aliens

On Location - Incredible Structures: Investigate 75 million years of credible evidence suggesting aliens have visited Earth. From cave drawings to phenomena in the skies. (S14, ep 11)

Giorgio Tsoukalos takes a look back at the most extraordinary encounters that, as far as he's concerned, provide evidence of an extraterrestrial presence on Earth.

Giorgio Tsoukalos takes a look back at the incredible hieroglyphs, petroglyphs, and geoglyphs that he believes tell a worldwide story of alien visitation.

Giorgio Tsoukalos takes a look back at the most compelling investigations of all, and events that he believes represent real encounters with extraterrestrial visitors.

Giorgio Tsoukalos takes a look back at the most compelling investigations of all, and events that he believes represent real encounters with extraterrestrial visitors.

Giorgio Tsoukalos takes a look back at the most compelling investigations of all, and events that he believes represent real encounters with extraterrestrial visitors.

Giorgio Tsoukalos takes a look back at the most compelling investigations of all, and events that he believes represent real encounters with extraterrestrial visitors.

Giorgio Tsoukalos takes a look back at the most compelling investigations of all, including events that he believes represent real encounters with extraterrestrial visitors.