The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. Easily Arizona’s most distinguishable landmark – and a natural wonder that you simply have to see to believe. Stretching 277 miles from end to end, steep, rocky walls descend more than a mile to the canyon’s floor, where the wild Colorado River traces a swift course southwest. Carved out by the Colorado River, the Grand Canyon is the most spectacular gorge in the world. Its horizontal strata retrace the geological history of the past 2 billion years. There are also prehistoric traces of human adaptation to a particularly harsh environment.