Between Joshua Tree and Death Valley in the eastern Mojave Desert, this 1.5-million-acre preserve encompasses Kelso Dunes — which rise 700 feet and boom with subsonic sound when sand cascades down their faces — and Cima Dome, home to the world's densest natural Joshua tree forest. Hole-in-the-Wall contains remarkable petroglyphs and a dramatic maze of rhyolite rock formations; the Kelso Depot, a restored 1924 Spanish Colonial Revival railroad station, serves as the visitor center.