Japan's Futuristic Underground Flood Tunnel.
A neat collection of photos of Japan's futuristic flood prevention system called G-CANS [wiki] in Edogawa:The G-Cans project (Shutoken Gaikaku Housui Ro, means drain outer Tokyo metropolitan area.) is an u...
https://www.neatorama.com/2006/06/24/japans-futuristic-underground-flood-tunnel/