Grand Canyon National Park
Grand Canyon National Park is the 15th site in the U.S. to have been named a national park. Named a UNESCO World Heritage Site in 1979, the park i slocated in northwester Arizona. The park's central feature is the Grand Canyon, a gorge of the Colorado River, which is often considered one of the Wonders of the World. The park, which covers 1.2 million acres of unincorporated area in Coconino and Mohave counties, received nearly six million visitors a year, which is the second highest of all national parts after Great Smoky Mountains National Park.