World's Most Extreme S1E6 backdrop
World's Most Extreme poster

World's Most Extreme (2014)

S1E6 Tunnels

Dec 15, 2014 Season 1 Episode 6 Documentary

Spanning from the Swiss Alps to bustling cities in Japan, tunnels showcase remarkable feats of engineering, yet they can also become sites of tragedy. Here are ten of the most extreme tunnels found around the globe.

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