Secret Underground - Verborgene Geheimnisse

Rob Nelson explores tunnels underneath Denver's downtown buildings.

A look at tunnels under Denver's Capitol building.

Rob Nelson

Rob Nelson

Rob Nelson

Rob Nelson and Stefan Burns overlook the vast Timna Valley at dawn. Here they will use unprecedented technology in the search for three thousand year old tombs.

Rob examines the landscape that surrounds California’s Mono Lake.

Rob Nelson

Rob Nelson and Stefan Burns explore the sand dunes of Mount Baldy with Park Ranger Laura Brenan.

Rob Nelson and Valerie Van Heest prepare for their dive to a shipwreck that could be the lost cargo vessel, the Thomas Hume.

Rob Nelson

Rob Nelson (l.)

Rob examines ancient Irish text in the Book of Kells.

Stefan Burns (l.); Rob Nelson (r.)

Rob Nelson and Stefan Burns explore the network of tunnels in the W?odarz complex. The W?odarz complex is part of the Riese Project which was constructed during World War II.

Rob Nelson (l.); Stefan Burns (r.)

Stefan Burns (l.); Rob Nelson (r.)

Rob Nelson (r.)

Rob talks to two members of the USGS team -- Lead scientist Luther Strayer (middle) and Geologist Rufus Catchings (right) -- about the detonations they are about to set off in the hills near the Hayward Fault.

Rob Nelson

Rob Nelson and Stefan Burns lower a videoscope into an air gap in the sand dunes of Mount Baldy as they try to determine its depth and learn more about it.

Rob Nelson

Rob Nelson drills through a wall in tunnels underneath Denver's downtown.