Here is something truly enormous, worthy of Japanese crazed super-scale imagination – vast caverns and otherworldly columns (looking like some kind of a temple) under Tokyo – an infrastructure “built for preventing overflow of the city’s major waterways and rivers during rain and typhoon season”.

THE G-CANS PROJECT, ALSO KNOWN as the Metropolitan Area Outer Underground Discharge Channel, is a massive underground waterway and water storage area built by the Japanese government to protect Tokyo from flooding during Japan’s severe monsoon seasons.

Begun in 1992, the two-billion-dollar project finally saw completion in 2009. The tunnels run over 100 kilometers, but perhaps the most impressive features of the drainage system are the 213-foot-tall silos and the 83-foot-tall, 580-foot-long pillared main tank commonly referred to as the “Underground Temple,” which was built to collect run-off from the city’s waterways.

The humongous drainage system can pump over 200 tons of water a second, and, over the past decade or so, has proved useful for well over a hundred times. It has also become a popular filming location and been featured in numerous movies, TV series, and music videos. Join the official tour, and be awed by the massive Underground Temple in person.