Great+Caninon

The **Grand Canyon** is a colorful steep-sided [|gorge] carved by the [|Colorado River] in the [|U.S.] state of [|Arizona]. It is largely contained within the [|Grand Canyon National Park] — one of the first [|national parks] in the United States. President [|Theodore Roosevelt] was a major proponent of conservation of the Grand Canyon area, and visited on numerous occasions to hunt and enjoy the scenery. The canyon, created by the [|Colorado River] over 6 million years, is 277 miles (446 km) long, ranges in width from 4 to 18 miles (6.4 to 24 kilometers), and attains a depth of more than a mile (1.6 km). Nearly two billion years of the [|Earth]'s 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. The Grand Canyon is a massive rift in the Colorado Plateau that exposes uplifted [|Proterozoic] and [|Paleozoic] strata. The Grand Canyon is unmatched throughout the world for the vistas it offers to visitors on the rim. It is not the deepest canyon in the world — both the [|Barranca del Cobre] in Northern Mexico and [|Hell's Canyon] on the Oregon-Idaho border are deeper — but Grand Canyon is known for its overwhelming size and its intricate and colorful landscape. Geologically it is significant because of the thick sequence of ancient rocks that are beautifully preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent. Grand Canyon is also one of the most spectacular examples of natural erosion in the world.