Humanity has launched satellites into outer space and submarines to the ocean floor, but the ground below Earth's surface remains shrouded in mystery. Are there profound secrets buried beneath layers of rock, or hidden in vast caves? See more in Season 6, Episode 1, "The World Beneath Our Feet." #TheUnXplained Subscribe for more from The UnXplained and other great The HISTORY Channel shows: http://histv.co/SubscribeHistoryYT Watch more The UnXplained on YouTube in this playlist: https://histv.co/UnXplainedYT Find out more about the show and watch full episodes on our site: https://histv.co/unxplained 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 From the producers of Ancient Aliens and The Curse of Oak Island comes The UnXplained, a one-hour, non-fiction series that explores the world’s most fascinating, strange and inexplicable mysteries. Hosted and executive produced by Golden Globe and Emmy Award-winning actor William Shatner (Star Trek, Boston Legal) each episode will feature compelling contributions from scientists, historians, witnesses and experiencers—each seeking to shed light on how the seemingly impossible actually can happen. The HISTORY® Channel, a division of A+E Global Media, 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.