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The Grand Canyon is a steep-sided gorge carved by the Colorado River in the U.S. state of Arizona, and parts of Nevada. 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 preservation of the Grand Canyon area, and visited on numerous occasions to hunt and enjoy the scenery.
View from the South Rim.Longstanding scientific consensus has been that the canyon was created by the Colorado River over a period of six million years, but research released in 2008 suggests a much longer 17 million year time span. The canyon is 277 miles (446 km) long, ranges in width from 4 to 18 miles (6.4 to 29 km) 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 "canyon started from the west, then another formed from the east, and the two broke through and met as a single majestic rent in the earth some six million years ago. The merger apparently occurred where the river today, coming from the north, bends to the west, in the area known as the Kaibab Arch."
Prior to European emigration, the area was inhabited by Native Americans who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon ("Ongtupqa" in Hopi language) a holy site and made pilgrimages to it. The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain, who arrived in 1540.In 1869, Major John Wesley Powell, a one-armed Civil War veteran with a thirst for science and adventure, made the first recorded journey through the canyon on the Colorado River. Powell referred to the sedimentary rock units exposed in the canyon as "leaves in a great story book
The Grand Canyon is a massive rift in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata and is also one of the six distinct physiographic sections of the Colorado Plateau province. 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 — Cotahuasi Canyon (11598 feet or 3535 m) and Colca Canyon (10499 feet or 3200 m), both in Arequipa, Peru, and Hell's Canyon (7,993 feet or2436 m) on the Oregon-Idaho border, are all 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 National Park is one of the world’s premier natural attractions, attracting about five million visitors per year. Overall, 83% were from the United States: California (12.2%), Arizona (8.9%), Texas (4.8%), Florida (3.4%) and New York (3.2%) represented the top domestic visitors. Seventeen percent of visitors were from outside the United States; the most prominently represented nations were the United Kingdom (3.8%), Canada (3.5%), Japan (2.1%), Germany (1.9%) and The Netherlands (1.2%).
Aside from casual sightseeing from the South Rim (averaging 7000 feet (2100 metres) above sea level), whitewater rafting, hiking and running are especially popular. The floor of the valley is accessible by foot, muleback, or by boat or raft from upriver. Hiking down to the river and back up to the rim in one day is discouraged by park officials because of the distance, steep and rocky trails, change in elevation, and danger of heat exhaustion from the much higher temperatures at the bottom. Rescues are required annually of unsuccessful rim-to-river-to-rim travelers. Nevertheless, hundreds of fit and experienced hikers complete the trip every year
Lipan Point is a promontory located on the South Rim. This point is located to the east of the Grand Canyon Village along the Desert View Drive. There is a parking lot for visitors who care to drive along with the Canyon's bus service that routinely stops at the point. The trailhead to the Tanner Trail is located just before the parking lot. The view from Lipan Point shows a wide array of rock strata and the Unkar Creek area in the inner canyon
In 1956 the Grand Canyon was the site of the deadliest commercial aviation disaster in the United States at the time.
On the morning of June 30, 1956, a TWA Lockheed Super Constellation and a United Airlines Douglas DC-7 departed Los Angeles International Airport within three minutes of one another on eastbound transcontinental flights. Approximately 90 minutes later, the two propeller-driven airliners collided above the canyon while both were flying in unmonitored airspace.
The wreckage of both planes fell into the eastern portion of the canyon, on Temple and Chuar buttes, near the confluence of the Colorado and Little Colorado rivers. The disaster killed all 128 passengers and crew members aboard both planes.
This accident led to the institution of high-altitude flightways and positive control by en route ground controllers
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