Unearthed: Season 6, Episode 4

6 - 4: Mount Rushmore: The Hidden Secrets

Mount Rushmore in the Black Hills of South Dakota is one of America's most iconic landmarks, but there are dark mysteries behind its presidential faces. Experts use cutting-edge tech and the latest science to reveal what lies beneath the rock and the secret history of its creation. The Crazy Horse Memorial in the Black Hills is also featured.