Ancient Aliens: Crystal City Discovered Under Antarctica (Season 18)

During an Arctic expedition, naval officer Richard Byrd makes a very unusual discovery, in this clip from Season 18, “Secrets of Inner Earth.“ Watch all new episodes of Ancient Aliens, Fridays at 9/8c, 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 documentary events, to a signature slate of industry leading nonfiction series and premium fact-based scripted programming, The HISTORY® Channel serves as the most trustworthy source of informational entertainment in media. The HISTORY® channel has been named the #1 U.S. TV network in buzz for seven consecutive years by YouGov BrandIndex, and a top favorite TV network by Beta Research Corporation. For a deeper dive, visit or follow @history on Instagram, Twitter, Facebook, YouTube and TikTok. For additional press materials visit the A E Networks Press Center at .