Metropolitan Area Outer Underground Discharge Channel

The Metropolitan Area Outer Underground Discharge Channel in Kasukabe is the largest underground flood diversion facility in the world, built to protect low-lying Tokyo from devastating floods during typhoon and rainy seasons. The massive underground temple-like space features 59 towering concrete pillars supporting a cavernous pressure-adjusting water tank that stretches 177 meters long and 78 meters wide. Public tours run daily and take visitors through the eerily beautiful main chamber, which has been used as a filming location for numerous movies and TV shows. Advance reservation is required, and the guided tours are available in both Japanese and English, making this one of the most unique engineering attractions in all of Japan.