On a 47-acre site north of Phoenix, Indians from throughout the Southwest carved more than 1500 petroglyphs, or rock etchings, along an ancient trade route. Between 500 and 5000 years old, these pictographs have an unknown meaning but may relate to hunting, religion, astronomy, or intertribal communication. Today, they're open to viewing along a quarter-mile trail; you can follow a guided tour or direct yourself among the boulders. Indoors, a video speculates on the nature of the carvings, and exhibits and a gift shop are available. This is a great museum for learning more about the Native American cultures that lives in the region for centuries.