A millennium-old Romanesque monastery located 50 kilometers (31 miles) north of Barcelona, Sant Miquel del Fai is most notable for its location on a cliff-face in the Catalonian countryside. The hike through the Tenes Valley from the bus stop to the mountainside is replete with gorgeous waterfalls and scenery, with two intriguing cave formations (Les Tosques and Sant Miquel) worth exploring as well. Check the official site for information on tours and when the abbey is open for visitors.
Location:Sant Feliu de Codines
Note:There is bus transport to the monastery if you're in a hurry to reach your destination; then again, you'd be missing a few hours of fantastic hiking.