Tokyo Flood Prevention, Insane underground tunnel system in Japan

Fifty metres under Tokyo lies a subterranean world 6. 4 kilometres of tunnels, water tanks and massive pillars constructed to withstand 200 tonnes of water per second. This engineering marvel built to protect the everpresent threat of Tokyo flooding. Subscribe to ABC Science YouTube Australians can watch Catalyst on ABC iview: This is an official Australian Broadcasting Corporation YouTube channel. Contributions may be removed if they violate ABC s Online Conditions of Use (Section 3).