The highest town in the Sierra Morena - guarded to its south by a small offshoot of the range - ARACENA has sharp, clear air, all the more noticeable after Sevilla. Capital of the western end of the sierra with 10,000 inhabitants, it's a substantial but pretty town, rambling up the side of a hill topped by the Iglesia del Castillo , a Gothic-Mudéjar church built by the Knights Templar around the remains of a Moorish castle.

 

Although the church is certainly worth the climb, Aracena's principal attraction is the Gruta de las Maravillas (daily 10.30am-1.30pm & 3-6pm; guided hourly visits, half-hourly at weekends; ¬5.40), the largest and arguably the most impressive cave in Spain. Supposedly discovered by a local boy in search of a lost pig, the cave is now illuminated and there are guided tours as soon as a dozen or so people have assembled. On Sunday there is a constant procession, but usually plenty of time to gaze and wonder. The cave is astonishingly beautiful, and funny too - the last chamber of the tour is known as the Sala de los Culos (Room of the Buttocks), its walls and ceiling an outrageous, naturally sculpted exhibition, tinged in a pinkish orange light. Close by the cave's entrance are a couple of excellent restaurants, open lunchtime only. Aracena is at the heart of a prestigious jamón -producing area, so try to sample some, and, when they're available, the delicious wild asparagus and local snails - rooted out from the roadside and in the fields in spring and summer respectively.