The Grand Canyon The Grand Canyon was formed by the downward cutting of the Colorado River over a span of millions of years. Located in Arizona, the Grand Canyon is 277 miles (446 kilometers) long, up to 18 miles (29 kilometers) wide, and more than 5000 feet deep (1500 meters). Uplift, erosion (from the downward cutting of the Colorado River), deposition of materials, and submergence are all shown from the rocks of the canyon. Plant life covers the walls of the canyon, from subtropical at the base to subarctic near the rims. Facts: -The first European to see the Canyon was the Spanish explorer, Garcia Lopez de Cardenas in 1540. 29 years later (1869), the U.S. explorer John Wesley Powell became the first party to lead a group of people through the bottom of the canyon in a boat. -In 1908, the Grand Canyon was set aside by the government as a National Monument. Grand Canyon Photos >> Natural Wonders >> Ancient Wonders >>