The United States national park system is one of the great outdoor inheritances in the world. Yosemite's valley of vertical granite — El Capitan, Half Dome, Bridalveil Fall — is America's most visited mountain landscape, but the backcountry above the valley carries week-long wilderness itineraries that most visitors never reach. The Grand Canyon's South Rim to River trail drops 1,500 metres through 1.8 billion years of geological time in a single day hike. Yellowstone is the world's largest active volcanic system — geysers, bison herds, and wolf packs in a national park where the ground temperature beneath the meadow is still measurable. The Pacific Crest Trail runs 4,279 kilometres from Mexico to Canada through three mountain ranges. The Florida Everglades is a slow-water wilderness of alligators, manatees, and roseate spoonbills navigable by canoe. Tours by locals often reveal the rhythm of the place in a more natural way. The hidden gems usually do the rest.