S1 E2 ∙ Sweden ∙
Exploring Sweden's passion for subterranean spaces, and how the nation has taken extraordinary precautions to protect itself - by excavating an astounding 65,000 nuclear bunkers.
Exploring Sweden's passion for subterranean spaces, and how the nation has taken extraordinary precautions to protect itself - by excavating an astounding 65,000 nuclear bunkers.
Incredible feats of human endeavour, revealing what people have built, where, how and why.
Exploring Sweden's passion for subterranean spaces.
A look at some of Switzerland's 300,000 subterranean bunkers built across history.
The wonders of the Wieliczka Salt mine in southern Poland.
A labyrinth of tunnels underneath a tiny French village.
An underground city beneath a forest in Northern France built to house 3,000 people.
The underground bases built by the German army during the occupation of Jersey.
The secrets of the largest subterranean fortress along France's border with Germany.
The sinister history of Edinburgh's underground vaults.
The military headquarters built beneath Dover Castle during the Second World War.