Underground Worlds

For centuries, people have built mind-blowing structures underground. This new and exclusive series reveals incredible feats of human endeavour and reveals what people have built, how they built it and why.

Underground Worlds

Underground Worlds

Series 2 | Episode 8

New. Exploring a former gold mine turned scientific laboratory in South Dakota. Plus, limestone tunnels in London and a former water cistern in Denmark.

Underground Worlds

Underground Worlds

Series 2 | Episode 3

Exploring the forgotten underworld hiding beneath the streets of Cincinati, USA. Plus, a state-of-the-art Cold War fortress on the shores of Denmark.

Underground Worlds

Underground Worlds

Series 2 | Episode 6

Exploring hidden defences that have kept Cork Harbour, in Ireland, safe for over 400 years. Plus, a former submarine base in the fjords of northern Norway.

Underground Worlds

Underground Worlds

Series 2 | Episode 10

New. Exploring caves beneath Orvieto in Italy, originally built by the Etruscans long before the Roman Empire. Plus, a former limestone mine under Kansas City.

Underground Worlds

Underground Worlds

Series 2 | Episode 7

Exploring long narrow tunnels beneath Exeter that were built in medieval times to protect the city. Plus, a marble quarry under the pine forests of Vermont.

Underground Worlds

Underground Worlds

Series 2 | Episode 1

Exploring the extensive air raid tunnels hidden beneath Ramsgate. Also, how the former thriving mining town of Butte, Montana repurposed the 10,000 miles of tunnels.

4 Hidden Places You Never Knew Existed

4 Hidden Places You Never Knew Existed

Here are just four of the strangest subterranean spots you never knew were there.