Caverns of Sonora, Caverns of Sonora Road off I-10 8 miles west of town, 325 387 6507, ]. Consistently called by speleologists as one of the most beautiful caves in the country, the cavern has a host of very unique, impossible-looking formations. Guided tours leave every half-hour for a somewhat strenuous 1.5 mile path underground.
Eaton Hill Wildlife Sanctuary. 37-acre nature park with 3 miles of hiking trails, with both Hill Country and Chihuahua Desert wildlife. Open during daylight hours. Free.