Grand Canyon National Park is one of the Seven Natural Wonders of the World, a designated World Heritage Site, and one of the Crown Jewels of the National Park System. Declared a national park in 1919, the mile-deep, 277-mile long gorge draws nearly five million visitors annually to the lofty rims and world-class whitewater that await the active traveler. The 1.2 million acre park is home to numerous animals (from the endangered California condor above, to cougars, rattlesnakes and Gila monsters below), over 1,500 species of plants, archaeological sites dating back thousands of years, and one of the most complete geologic cross sections visible anywhere on the planet.  Sustaining these plant and animal communities, as well as carving the Canyon ever-deeper, is the powerful Colorado River, the lifeblood of the desert Southwest.         (video credit: aerial filmworks)