Since two researchers suggested last year that the Grand Canyon was carved 70 million years ago (much older than the consensus of 6 million years), a rousing debate over the canyon's true age has played out at scientific meetings, through email, and now, in the pages of a respected journal. Full story
Tightrope daredevil Nik Wallenda announces his most death-defying stunt yet: walking across the Grand Canyon on with no safety harness.
This mosaic of Mars is a compilation of images captured by the Viking Orbiter 1. The center of the scene shows the entire 2,500-mile Valles Marineris canyon system, which is five times as long as the Grand Canyon. The image is part of "MARS 2K4," an exhibit on display at the National Geographic Muse
RNPS IMAGES OF THE YEAR 2012 - Visitors have a view of the Grand Canyon and the Colorado River flowing below from a skywalk extending out over the Grand Canyon and its incomplete building, on the Hualapai Indian Reservation, Arizona February 28, 2012. The tiny Hualapai nation, in a bold move that c
With the North Rim in the background, tourists hike along the South Rim of the Grand Canyon Tuesday, Feb. 22, 2005, in Grand Canyon, Ariz. Conservation groups have finalized the purchase of two private northern Arizona ranches, protecting 900,000 acres of wilderness, including land stretching along