The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the 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 preservation of the Grand Canyon area, and visited it on numerous occasions to hunt and enjoy the scenery.
The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (1.83 km) (6000 feet). Nearly two billion years of the Earth’s geological 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 the specific geologic processes and timing that formed the Grand Canyon are the subject of debate by geologists, recent evidence suggests the Colorado River established its course through the canyon at least 17 million years ago. Since that time, the Colorado River continued to erode and form the canyon to the point we see it at today.
Grand Canyon National Park is one of the world’s premier natural attractions, attracting about five million visitors per year. Within the park lies the Grand Canyon, a gorge of the Colorado River, considered to be one of the major natural wonders of the world. The two rims of the Canyon are connected via Las Vegas, Nevada, and the Hoover Dam. The rest of the Grand Canyon is extremely rugged and remote, although many places are accessible by pack trail and backcountry roads.
In 1979, UNESCO declared it as a World Heritage Site. The Grand Canyon itself, including its extensive system of tributary canyons, is valued for the combination of large size, depth, and the exposed layering of colorful rocks dating back to Precambrian times.