By some measures, this is the deepest canyon in the United States by over a mile and a half. With its distinctive rock outcroppings, skyscraping trees and deep valleys, this is the place where John Muir once called "a rival to Yosemite." Located right next to Sequoia National Park, this park has rivers to play in, long hikes in the Sierra Nevadas, and caves to explore, along with a touch of Sequoia trees to boot!