An Aerial view of the less-visited lower Grand Canyon West. The Grand Canyon is a steep-sided canyon carved by the Colorado River in the state of Arizona in the US. It is 277 miles (446 km) long and up to 18 miles (29 km) wide, and attains a depth of over a mile (6,000 feet / 1,800 meters). [Photo by Xu Lin / China.org.cn]