The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km)

long, 18 miles (29 km) wide and attains a depth of more than a mile (6,093 feet or 1,857 m).The canyon and adjacent rim are contained

within Grand Canyon National Park, Kaibab National Forest, Grand Canyon-Parashant National Monument, Hualapai Indian Reservation,

Havasupai Indian Reservation and Navajo Nation. President Theodore Roosevelt was a major proponent of preserving the Grand Canyon area

and visited it on several occasions to hunt and enjoy the scenery.Nearly two billion years of Earth's geological history have

been uncovered as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau

was raised. While some aspects about the history of the canyon incision are debated by geologists,several recent studies

support the hypothesis that the Colorado River established its course through the region about 5 to 6 million years ago. Since that

time, the Colorado River has prompted erosion of tributaries and retreat of rocks, as well as deepening and widening of the canyon.

time, the Colorado River has prompted erosion of tributaries and retreat of rocks, as well as deepening and widening of the canyon.