Best Urban Exploration

Some 11 blocks of shaded wildness through the heart of the city, High School Wash tiptoes along the nature/culture edge. On a recent walk, we discovered an oriole's nest and a bounty of native vegetation, and were serenaded by doves and cactus wrens. Kids' secret play spaces, an occasional creekside bench and privately tended guerilla parks reward the curious adventurer. Each avenue's culvert hosts a different subculture, identifiable by its graffiti: the rich iconography of hippies, stoners, skaters, punks and middle schoolers with hilarious sexual obsessions. Start on Campbell Avenue between Seventh and Eighth streets, and follow the wash downstream to Euclid Avenue. Want a walk on the wilder side? Take a flashlight and continue west through the tunnel that goes under Tucson High and surfaces on Third Avenue; just beware of storms and flash floods.