Grand Canyon is one of the most spectacular canyons in the world. It cuts through northwestern Arizona in Grand Canyon National Park (see Grand Canyon National Park ). The Grand Canyon extends 277 miles (446 kilometers). It is about 1 mile (1.6 kilometers) deep. The canyon varies in width from less than 1 mile to 18 miles (29 kilometers).
The Colorado River flows through the canyon. The river formed the canyon over millions of years by cutting through layers of limestone, sandstone, shale, and other rocks. The rock layers vary in shade and color, and the tones seem to change during the day. At sunset, the red and brown layers in the walls of the canyon are especially brilliant.
Climate.
Temperatures at the bottom of the canyon may be as much as 25 Fahrenheit degrees (14 Celsius degrees) higher than at the top. The average annual rainfall varies from 7 inches (18 centimeters) at the bottom of the canyon to 26 inches (66 centimeters) on the highest part of the rim. The variations in elevation and climate create several different zones, which have a wide variety of wildlife.
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Wildlife.
Hundreds of species of birds live in the Grand Canyon area. The area also has many other kinds of animals, including beavers, bighorn sheep, elk, lizards, mountain lions, mule deer, pronghorns, and snakes. White-tailed Kaibab squirrels and pink Grand Canyon rattlesnakes live only in the area.
Vegetation.
Ponderosa pine trees thrive on the canyon’s rim. On the south side, juniper and pinon pines grow in lower areas. Aspen, fir, and spruce live at the highest elevations in the north. Cactuses grow throughout the canyon area, especially in low areas.
History.
Some rocks in the deepest part of the Grand Canyon date back roughly 2 billion years. The Colorado River began to form the Grand Canyon about 6 million years ago. Through the centuries, the water eroded the layers of rock, forming the canyon. Fossils found in the canyon walls indicate that animals and plants lived in the area millions of years ago.
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Various Indian tribes have lived in the Grand Canyon during the last 4,000 years. Today, about 450 members of the Havasupai tribe live on a reservation in a side canyon called Havasu Canyon.
In 1540, a group of Spanish explorers led by García López de Cárdenas became the first Europeans to see the Grand Canyon. They were part of Francisco Vásquez de Coronado’s expedition to the area. In 1869, the American geologist John Wesley Powell became the first white person to lead a river expedition through the vast canyon, which he named the Grand Canyon.
In 1919, Grand Canyon National Park was established. The park consists almost entirely of the Grand Canyon.
See also Colorado River ; Grand Canyon National Park ; Seven natural wonders of the world .
