In northern Arizona, the Grand Canyon is a mile-deep gorge. According to scientists, the Colorado River cut a channel through layers of rock 5 to 6 million years ago, forming the canyon. In and around the canyon, humans have lived since the last ice age. Spaniards were the first Europeans to reach the Grand Canyon in the 1540s. The Grand Canyon was first protected as a forest reserve by President Benjamin Harrison in 1893, and it was made a national park by President Theodore Roosevelt in 1919. advertisement In northern Arizona, northwest of Flagstaff lies the Grand Canyon. It is
