The region’s most impressive natural attraction, the Reserva de la Biosfera El Pinacate y Gran Desierto de Altar (ranger station daily 9am–5pm; M$40; t638/384-9007), lies 52km north of Puerto Peñasco on Hwy-8. NASA used this otherworldly expanse of volcanic cinder cones and craters to train its astronauts for lunar landings. One of Pinacate’s largest and most awe-inspiring craters, “El Elegante”, is 1.6km wide and 250m deep and can be seen from space. Camping is allowed by arrangement with the ranger station at the edge of the park; permits are given on a first-come, first-served basis but there are no facilities. No public transport runs to Pinacate, so you’ll have to drive or join a tour.