Grand Canyon National Park
Unique combinations of geologic color and erosional forms decorate a canyon that is 277 river miles (446km) long, up to 18 miles (29km) wide, and a mile (1.6km) deep.
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the state of Arizona in the United States. It is contained within and managed by Grand Canyon National Park, the Kaibab National Forest, Grand Canyon-Parashant National Monument, the Hualapai Tribal Nation, the Havasupai Tribe and the Navajo Nation.
grand canyon grand

grand-c2 grand-c3

grand-c4 grand-c5
Long-axis length: 277 miles (446 km)
Width: 4 to 18 miles (6.4 to 29.0 km)

grand-c9

References: http://www.nps.gov/grca/index.htm