Tonto National Monument

This is a National Monument in the Superstition Mountains, in central Arizona. The area lies on the northeastern edge of the Sonoran Desert ecoregion, an arid habitat with annual rainfall of about 16 inches here. The Salt River runs through this area, providing a rare, year-round source of water. Major features of the 1.8-square-mile monument are the Lower Ruin, consisting of a 16-room ground floor with some second-story rooms and a neighboring 12-room annex, and the Upper Ruin, which has a 32-room ground floor, a second story, and terraces and rooftop space. Although some of the rooms are well-preserved, exposure to weather has taken a toll.