San Juan de la Peña sits about 20km southwest of Jaca, partly built into a massive sandstone overhang at the foot of a cliff. The setting is extraordinary: the old monastery's Romanesque church and cloister emerge directly from the rock face, with the cliff forming the ceiling of the cloister and part of the nave. The famous carved capitals in the cloister — depicting scenes from the Old and New Testaments in a vivid, somewhat eccentric Romanesque style — are among the most important examples of 12th-century Aragonese sculpture.
A newer monastery was built on the plateau above in the 17th century after the original was damaged by fire; both are open to visitors. The road up through the oak and beech forests is beautiful, and there are good walks in the area. A car is necessary — there is no public transport — but it is an easy day trip from Jaca, about 30 minutes each way.