Seven Natural wonders of the world

Grand Canyon

The Grand Canyon is a very 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 the Grand Canyon area, visiting on numerous occasions to hunt and enjoy the scenery.
The canyon, created by the Colorado River cutting a channel over about 6 million years, is 277 miles (446 km) long, ranges in width from 4 to 18 miles (0.4 to 24 kilometers), and attains a depth of more than a mile (1.6 km). Nearly two billion years of the Earth's history has been exposed as the Colorado River and its tributaries cut through layer after layer of sediment as the Colorado Plateaus have uplifted.
The first recorded sighting of the Grand Canyon by a European was in 1540, García López de Cárdenas from Spain. The Grand Canyon was largely unknown until after the U.S. Civil War. In 1869, Major John Wesley Powell, a one-armed Civil War veteran with a thirst for science and adventure, made a pioneering journey through the canyon on the Colorado River. He accomplished this with nine men in four small wooden boats, though only six men completed the journey. His party was, as far as we know, the first ever to make such a trip. Powell referred to the sedimentary rock units exposed in the canyon as "leaves in a great story book". Long before that, the area was inhabited by Native Americans who built settlements within the canyon walls and its many caves.

Geography
The Grand Canyon is a massive — in places over a mile (1609 m) deep — 277 miles (446 km) long 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 in Idaho 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.
Uplift associated with mountain building events later moved these sediments thousands of feet upward and created the Colorado Plateau. The higher elevation has also resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid. The uplift of the Colorado Plateau is uneven, and the north-south trending Kaibab Plateau that Grand Canyon bisects is over a thousand feet higher at the North Rim (about 300 meters) than at the South Rim. The fact that the Colorado River flows in a curve around the higher North Rim part of the Kaibab Plateau and closer to the South Rim part of the plateau is also explained by this asymmetry. Ivo Lucchitta of the U.S. Geological Survey first suggested that, as the Colorado River developed before significant erosion of the region, it naturally found its way across or around the Kaibab Uplift by following a "racetrack" path to the south of the highest part of the plateau. Almost all runoff from the North Rim (which also gets more rain and snow) flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon (following the general tilt). The result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side.
Temperatures on the North Rim are generally lower than the South Rim because of the greater elevation (averaging 8000 feet (2438 meters) above sea level). Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon (Arizona State Route 67) is limited during the winter season due to road closures. Views from the North Rim tend to give a better impression of the expanse of the canyon than those from the South Rim.