Concierge.com's insider take:
The 16,000-acre South Mountain Park in South Phoenix—the world's largest city park—has 51 miles of beautiful desert wilderness trails for hikers, bikers, and horseback riders (10409 S. Central Ave.; 602-534-6324; www.phoenix.gov/PARKS/hikesoth.html). Most trails are more of a stamina test than a measure of climbing skill. For more technical climbing, head to Camelback Mountain, which sits smack in the middle of the city. The best way to hike it is to start on the northwest side, at Echo Canyon Recreation Area (Tatum Blvd. and McDonald Dr., Paradise Valley; 602-256-3220; www.phoenix.gov/PARKS/hikecmlb.html). The moderate hike up to the camel's head takes about two hours round-trip and rewards you with one of the best perspectives of the Valley. Serious hikers should tackle the trek to the top: the peak of Camelback's main hump, 2,704 feet above sea level. You'll learn to pull yourself up by any means possible (there are rails) and then can carefully navigate your way down.