S1 E8 ∙ The Maginot Line ∙
The secrets of the largest subterranean fortress along France's border with Germany, and a look at how a unique precious mineral was discovered in Derbyshire.
All episodes for series 1 of Underground Worlds
S1 E1 · Gibraltar
Incredible feats of human endeavour, revealing what people have built, where, how and why.
S1 E2 · Sweden
Exploring Sweden's passion for subterranean spaces.
S1 E3 · Switzerland
A look at some of Switzerland's 300,000 subterranean bunkers built across history.
S1 E4 · Kingdom of Salt
The wonders of the Wieliczka Salt mine in southern Poland.
S1 E5 · Bouzincourt
A labyrinth of tunnels underneath a tiny French village.
S1 E6 · City of Naours
An underground city beneath a forest in Northern France built to house 3,000 people.
S1 E7 · Jersey War Tunnels
The underground bases built by the German army during the occupation of Jersey.
S1 E8 · The Maginot Line
The secrets of the largest subterranean fortress along France's border with Germany.
S1 E9 · Edinburgh Vaults
The sinister history of Edinburgh's underground vaults.
S1 E10 · Dover War Rooms
The military headquarters built beneath Dover Castle during the Second World War.
