Last Straw: How The Fortunes Of Las Vegas Will Rise Or Fall With Lake Mead - Popular Science

The bathtub ring can be seen for miles. The 120-foot-high band of rock, bleached nearly white by mineral-rich water, circles the shoreline of Lake Mead. Water levels have dropped by almost 100 feet in the past decade, and the ring has emerged as a stark reminder of the drought enveloping the American Southwest.