Photo: Grand Canyon

The Grand Canyon is a steep-sided gorge carved by the Colorado River in the U.S. state of Arizona. It is largely contained within the Grand Canyon National Park, one of the first national parks in the United States. The canyon is 277 miles long, ranges in width from 4 to 18 miles and attains a depth of more than a mile. Nearly two billion years of the Earth's history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted.