129 of 376

United States

Grand Canyon panorama. The Grand Canyon began to take shape some 5 to 6 million years ago as the Colorado Plateau was uplifted. The Colorado River and its tributaries and channels cut through nearly two billion years of Earth’s geological history in the Plateau, making the Grand Canyon a geologist’s mecca. The Grand Canyon is 446 km (277 mi) long, up to 29 km (18 mi) wide, and attains a depth of over a mile (1,857 m or 6,093 ft). Image courtesy of the National Park Service.