Grand Canyon National Park, Arizona
The Grand Canyon, one of the Seven Natural Wonders of the World, is best known for its size, depth, rock formation, and coloration. The vast canyon was formed during three to six million years of geological activity and erosion by the Colorado River, which continues to alter its contours. The canyon boasts impressive waterfalls and rapids. It is 277 river miles (446 kilometers) long, up to 18 miles (29 kilometers) wide, and a mile (1.6 kilometers) deep.
Photograph by Kevin Byrne, My Shot