Hidden Tokyo: The Underground Temple Guarding the City

By / MOOK Scenic Spots Family Travel Life Network Editorial Department, compiled and reported by Liao Qiyu

No one would have imagined that beneath Tokyo’s developed skyline lies a mysterious and serene underground space, where over fifty massive pillars stand in orderly rows. Standing quietly beside these columns highlights both the vastness of the space and your own insignificance, as if you’ve stepped onto a movie set—the so-called “Underground Temple” sparks endless curiosity.

This “underground temple” is actually the “Capital W Outer Moat Diversion Channel,” an underground drainage system hidden beneath Saitama Prefecture in Tokyo Metropolis. To manage Tokyo’s high population density, the Japanese government constructed this world-class drainage facility deep underground at a depth of50meters. Centered around five reservoir shafts as tall as eight-story buildings—each resembling colossal cans—locals dubbed this place the “Underground Temple.” These five massive “cans” are supported by fifty-nine concrete pillars, each weighing500tons, standing upright like soldiers in the subterranean space. Together, they create a solemn scene reminiscent of ancient Greek temples, which has made the Underground Temple a famous tourist attraction and a popular filming location for movies and commercials. During the rainy season, floodwaters from major rivers in the metropolitan area are channeled through these five enormous reservoirs, then discharged via the Edogawa River, protecting the region from water disasters. Additionally, the reservoirs can function as underground water storage when necessary, showcasing their remarkable regulatory capabilities.