In 1963, humans stopped time, when the brand-new Glen Canyon Dam on the Utah-Arizona border cut off the reddish sediment that naturally eroded the Grand Canyon. Today the river runs vodka clear ...

To critics, Glen Canyon Dam was one of the U.S.'s biggest environmental mistakes. But it generates electricity for about 5 million people in seven states.

Drop in the water released from Glen Canyon Dam will temporarily change the Grand Canyon, revealing parts of the Colorado River not seen in decades, USGS said. U.S. Geological Survey (USGS ...