About 1,000 years ago, outside what is now Flagstaff, a cinder cone in the San Francisco Volcanic Field blew its top, showering the surrounding area with lava and ash. Since then, the minerals in the soil around the rim of the crater rusted, creating a striking red ring that lends the name Sunset Crater. A national monument was created here in 1930 when locals protested the plan of filmmakers to detonate explosives on the side of the slope. The main attractions at the small park are the visitor center, with its interactive volcano exhibits, and the short Lava Flow Trail that loops around the base of the volcano. Visitors can’t climb to the edge of Sunset Crater, but for those interested in scaling a volcano, the Lennox Crater Trail is open to hikers.