Grand Canyon

S2, E1: Almost 200 miles long and over a mile deep, this deep scar in the American Southwest is easily visible from space. You could stack five Empire State Buildings one on top of the other--and they still wouldn't reach the lip of the Canyon. As the Pacific grinds into the North American plate, a giant plateau has been pushed up over a mile in the air. Meanwhile, the Colorado River has been draining the Rockies, and with its thick load of sediment, continues to carve this amazing canyon in the rising plateau.