The Grand Canyon is a steep-sided canyon carved by the Colorado River in the state of Arizona in the United States of America. The canyon is 277 miles (446 Kms) long, up to 18 miles (29 Kms) wide and attains a depth of over a mile (6093 feet or 1857m).

Nearly two billion years of Earth's Ecological 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. While some aspects of history are debated, several recent studies support the hypothesis that the Colorado River established its course about 5 or 6 million years ago.