November 11, 2012, 5am PST
Will Hunt explores Paris beneath the surface during a 14-mile trek underground with a group of urban explorers, and finds subterranean sights to rival those found on the famous streets above.
February 3, 2011, 6am PST
Beneath Paris is an underground network of tunnels and quarries, long closed to the public. <em>National Geographic</em> takes a tour of this forbidden part of the city, where urban explorers keep tradition alive.
May 7, 2009, 5am PDT
A new mapping project is creating a comprehensive 3D image of the catacombs beneath Rome.