The Grand Canyon in Arizona is a geologic museum of epic proportions. In one panoramic sweep you can see nearly half of the earth's 4.6-billion-year history. Erosion has exposed rock strata ranging from the 1.7-billion-year old Vishnu Schist of the inner gorge, to the pale Kaibab Limestone deposited 250 million years ago. The Grand Canyon began to appear about 70 million years ago. It took another 5 to 6 million years for the wind, rain, ice, gravity and sediment-laden Colorado to widen the canyon to its present 10-mileaverage width.

Originally released by Switch International, 2007. Streaming video file encoded with permission for digital streaming by Infobase on May 06, 2015.

Grand Canyon: Landmarks (5:00); .