Colca Canyon is a canyon of the Colca River in southern Peru. It is located about 100 miles (160 kilometers) northwest of Arequipa. It is more than twice as deep as the Grand Canyon in the United States at 4,160 m., and it is promoted as the "world's deepest canyon," although the canyon's walls are not as vertical as those of the Grand Canyon. The Colca Valley is a colorful...