Buenos Aires National Wildlife Refuge
Encircled by seven mountain ranges in the Altar Valley, remote Buenos Aires National Wildlife Refuge is the only place in the United States where the Sonoran-savanna grasslands that once pervaded this region can still be seen. The U.S. Fish and Wildlife Service oversees this 115,000-acre preserve, managing programs to restore native grasses and protect endangered species such as the masked bobwhite quail. Birding and wildlife-viewing are popular here.