The Homestake Gold Mine in South Dakota is currently home to a nuclear research lab 4800 feet below the surface. But a proposed "Deep Underground Science and Engineering Lab" would extend the site to more than a mile and a half below the surface.
Narrator: They're mysterious, off limits and buried right under our feet. On the border a crack team of federal agents battle drug lords underground. Beneath a glittering sin city a vast network of tunnels protects a trillion dollar industry. Under a Tennessee town, subterranean scientists smash atoms at light speed. Now, it's time to unearth the surprising story of America's Secret Underground, on Modern Marvels.