Hidden in plain sight is an intimidating Chinese weapon that allows it to hold a quarter of the world’s population hostage without firing a single shot. While much attention has been given to the nation’s fearsome new military hardware, a formidable component in its arsenal has largely escaped notice: dams. With more than 87,000 dams and control of the Tibetan plateau, the source of ten major rivers which 2 billion people depend on, China possesses a weapon of mass destruction. With the flip of a switch, the Middle Kingdom can release hundreds of millions of gallons of water from its mega dams, causing catastrophic floods that would reshape entire ecosystems in countries downstream.