Created by the powerful force of the Colorado River. The Grand Canyon is estimated to be over 6 million years old. The canyon is 277 miles long and over 18 miles wide. The rocks found at the bottom of the canyon are said to be 2 billion years old. The Grand Canyon became a national park in 1919 and it is the 17th national park established in the United States. The Grand Canyon is a UNESCO World Heritage site and listed as one of the New World Wonders of the World.