Humans store water in huge metal towers and deep concrete reservoirs. But nature's water storage is much more scenic—the snowpack that tops majestic mountains. Even if we don't realize it, humans rely on those natural water towers just as much if not more than the ones we build. When the spring rains and summer sun melt this snowpack, it flows downhill to thirsty landscapes and humans. It provides water when precipitation is at its lowest and refills natural and built reservoirs. About a quarter of the world relies on the water stored in mountains.