GPS: 33°32'N 112°04'W
So big is South Mountain Park (16,500 acres [6,677 hectares] to be exact) that its sun-blasted expanse contains not one but three mountain ranges. A well-designed network of trails explores rocky heights and cactus-speckled desert, anchored by the 14.3-mile-long (23-kilometer-long) National Trail, which runs the length of the park on a high ridge.
Vitals: Get maps at the South Mountain Environmental Education Center; phoenix.gov/parks.
Originally published in the April 2008 edition of National Geographic Adventure