The Grand Canyon is an immense gorge carved by the Colorado River across northern Arizona, stretching roughly 277 miles in length, reaching up to 18 miles in width, and plunging more than a mile deep. Its layered bands of red, ochre, and violet rock expose nearly two billion years of geologic history, recording ancient seas, deserts, and mountain ranges in stone. Home to the Havasupai, Hualapai, Hopi, Navajo, and other Indigenous peoples for millennia, the canyon was designated a national park in 1919 and now draws close to six million visitors each year, who come to watch light and shadow shift across its vast escarpments from the crowded South Rim, the quieter and higher North Rim, or from the river itself far below.