

The Kaibab Trail, running right to left in the center, at the Grand Canyon National Park. The Associated Press
The Grand Canyon National Park is covered in morning sunlight. The Associated Press
A double rainbow forms at Hopi Point, after a rain shower at Grand Canyon National Park in Arizona. The Associated Press
A view from the South Rim of the Grand Canyon National Park in Arizona. The Associated Press
People on the Skywalk at the Grand Canyon. The Associated Press
Indian Watchtower at Desert View, South Rim of the Grand Canyon is shown in 1933. The Associated Press
An unfrequented segment of the Grand Canyon is seen from the waters of Boulder Lake, Ariz., in 1935. The Associated Press
Albert Einstein poses, wearing a headdress, with his wife, Elsa Einstein, and a Hopi tribe in Grand Canyon, Ariz., in 1931. The Associated Press
A group on horseback travels up a path at the Grand Canyon in Arizona in 1938. The Associated Press
Eric Gray, a trails maintenance worker at the Grand Canyon, leads a group of mules carrying supplies down a popular park trail. The Associated Press
A tour helicopter lifts off inside the Grand Canyon. The Associated Press
Rafters take a break from the rapids at Redwall Cavern in Marble Canyon near Grand Canyon National Park,. The Associated Press
John Hassberger of Waterford, Mich., watches the sunset from a ledge at Hopi Point in Grand Canyon National Park, Ariz. The Associated Press
Visitors stand at the Grand Canyon's Yavapai Point. The Associated Press
An aerial view of Grand Canyon National Park in Arizona. The Associated Press