The Grand Canyon is one of the most remarkable natural wonders in the world. Located in the state of Arizona, USA, it is one of the deepest gorges on Earth with an average depth of one mile (1.6km) and an average width of ten miles (16km). The canyon was carved over the past 6 million years by the action of the Colorado River as it drops over 2,200 feet (670m) along the 277-mile (446 km) length of the gorge.
The canyon isn't just a single gorge, however, but also includes numerous side canyons created by erosion. Because many layers of rock were exposed during this process, the walls of the canyon are countless shades of brown, yellow, red and gray. As the sun moves across the sky the light changes making the vista transform dramatically over the course of the day. The rock levels represent a cross-section of the geological history of the earth with the stone near the river being some of the oldest on the planet with an age of nearly two billion years.
