Giant underground tunnels swallow entire rivers to stop floods
Deep beneath Tokyo, massive concrete pillars weighing five hundred tons each support a subterranean cathedral designed to hold enough floodwater to fill one hundred Olympic pools.
Hidden seventy meters below the bustling streets of Saitama, the Metropolitan Area Outer Underground Discharge Channel functions as the city's secret mechanical lung. The heart of this system is a gargantuan pressure-adjusting tank nicknamed the Underground Temple, which features fifty-nine massive concrete pillars that stabilize the structure against the immense pressure of the surrounding earth. When typhoons strike, five enormous silos—each deep enough to house the Statue of Liberty—swallow the overflow from local rivers through a six-kilometer network of tunnels.