S1 E1 • Secrets of the Rock

A hidden, subterranean city built within the Rock of Gibraltar was an immense fortress to control the seas during World War II, and new discoveries reveal the secrets of a long-lost chamber with evidence of high-stakes espionage.

Première diffusion : 17 octobre 2019

S1 E2 • Mystery of the Lost Labyrinth

A strange, centuries-old labyrinth built into an abandoned quarry was built by an eccentric millionaire, and no one knows why; but now, a new excavation into this mysterious 9,000-foot tunnel system might finally reveal its dark secrets.

Première diffusion : 24 octobre 2019

S1 E3 • Secrets of the Terror Tunnels

A vast system of tunnels built almost three thousand years ago was the site of the greatest battles of antiquity, and these disorienting passages could be the deadliest weapon in war; experts reveal what made this underground world so terrifying.

Première diffusion : 31 octobre 2019

S1 E4 • The Renegade's Lair

A strange underground system known as the Black Cave is connected to a fairytale castle and was home to an infamous nobleman on the run from the law; today, experts investigate the secrets he left here to discover new parts of this mysterious network.

Première diffusion : 7 novembre 2019