Journey deep beneath the surface to uncover hidden tunnels, forgotten chambers, and long-lost secrets buried under Rome, Istanbul, and the remnants of Hitler’s last wartime projects. See more in this marathon from Pawn Stars. Watch all new episodes of Cities of the Underworld, returning soon, and stay up to date on all of your favorite The HISTORY Channel shows at history.com/schedule. #CitiesoftheUnderworld Subscribe for more from Cities of the Underworld and other great The HISTORY Channel shows: http://histv.co/SubscribeHistoryYT 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 HISTORY® is the leading destination for award-winning original series and specials that connect viewers with history in an informative, immersive, and entertaining manner across all platforms. The network’s all-original programming slate features a roster of hit series, premium documentaries, and scripted event programming.