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Grand Canyon
The Colorado River's mile-deep masterpiece carved through northern Arizona
Few landscapes overwhelm the senses like the Grand Canyon, a chasm 446 kilometres long and more than a mile deep that the Colorado River has sliced through the layered rock of northern Arizona. Stand at the rim and the scale defeats comprehension: ranks of buttes and side canyons recede in bands of rose, ochre, and slate toward a river that looks, from above, like a thread of green. It is less a single gorge than a vast eroded amphitheatre, exposing nearly two billion years of Earth's history in its walls.
The canyon is the work of the Colorado River, which over the past five or six million years has cut down through the rising Colorado Plateau, while wind, rain, and frost widened the gulf into the chasm seen today. It runs about 446 kilometres and plunges to a depth of roughly 1,857 metres, up to 29 kilometres wide. Its walls are a stacked geological library, the oldest rocks at the bottom near two billion years old, the youngest near the rim, each layer a chapter in the deep past of the continent.
People have lived in and around the canyon for thousands of years, and several Native nations, among them the Havasupai, Hualapai, Hopi, and Navajo, hold it sacred and still call its rim and depths home. Spanish explorers glimpsed it in 1540, but it was John Wesley Powell's daring 1869 river expedition that fixed it in the American imagination. Protected as a national park since 1919 and a World Heritage site, the Grand Canyon now draws millions of visitors a year to one of the planet's great natural spectacles.