Ancient Aliens: Terrifying Humanoids Emerge from Subterranean Realm (Season 18)

A new subterranean realm is discovered deep in the caves of Vietnam, in this clip from Season 18, “Secrets of Inner Earth.“ Watch all new episodes of Ancient Aliens, Fridays at 8/7c, and next day on The HISTORY Channel website at #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: Find out more about the show and watch full episodes on our site: Check out exclusive The HISTORY Channel content: History Newsletter - Website - Facebook - Twitter - “Ancient Aliens“ explores the controversial theory that extraterrestrials have visited Earth for millions of years. The HISTORY® Channel, a division of A E Networks, is the premier destination for historical storytelling. From best-in-class doc