Full Episode

Aired: 6/22/2014 | 0:54:41 | Expires: 6/22/2024 | Episode
On the surface, London is a buzzing, modern metropolis—but underneath lies a secret, hidden world, all but forgotten by the millions of people above. This program uncovers 2,000 years of subterranean history: a world of ancient caves and perfectly preserved Roman remains; mysterious rivers and gruesome plague pits; impenetrable vaults and top-secret bunkers.