25 million people rely on water from Lake Mead, and it's drying up

A persistent drought in the American Southwest forced the Anasazi to abandon their settlements a thousand years ago. Eventually the precipitation returned. Hoover Dam in Nevada was built in 1931, 'during an especially wet period for the West.' But today Lake Mead, which powers Hoover Dam's generators, is at an all-time low.  — Read the rest