Modern civilization relies on water’s incompressibility—it’s something we take for granted. Hydraulic systems harness the virtual non-compressibility of fluids like water or oil to multiply mechanical force. Bulldozers, cranes, and other heavy machinery exploit the physics of hydraulics, as do automobile brakes, fire sprinkler systems, and municipal water and waste systems. It takes extraordinary pressure to compress water. Even at the bottom of the deepest oceans, two and a half miles under the surface, where pressure is equal to about 1000 atmospheres, water is compressed by only 5 percent.