The notion of a universe inhabited by alien creatures can be found just about everywhere in American popular culture. But could mankind really have been visited by alien beings from other worlds? See more in Season 2, Episode 1, "The Ancient Astronaut Cover-Up." Stay up to date on all of your favorite The HISTORY Channel shows at history.com/schedule. #AmericasBookofSecrets Subscribe for more from America's Book of Secrets and other great The HISTORY Channel shows: http://histv.co/SubscribeHistoryYT Watch more America's Book of Secrets on YouTube in this playlist: https://www.youtube.com/playlist?list=PLob1mZcVWOahXrQrSF4qh4nXxElc6lo72 Check out exclusive The HISTORY Channel content: History Newsletter - https://histv.co/newsletter Website - https://histv.co/History Facebook - https://histv.co/Facebook Twitter - https://histv.co/Twitter 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 history.com or follow @history on Instagram, Twitter, Facebook, YouTube and TikTok. For additional press materials visit the A+E Networks Press Center at http://press.aenetworks.com.