The historic quarter of Ainsa, is a group of medieval houses packed tightly together, among which the slender tower of the church stands tall. On top of the rise the enormous premises of the castle looms and is almost as big as the rest of the town.

The walls that surrounded the town centuries ago remain almost intact until today and the town itself is filled with monuments that take us back to the Middle Ages. Adjacent to the square, lined by beautifully arched porches on both sides, we have the Romanesque church of Santa Maria, which dates from the first half of the 11th century. There you can admire the main facade, interesting crypt and the tower which dominates the small town. The cloister were built some time later, during the 13th century.

To the north-east of the city centre we find the citadel. Its origins date back to a pentagonal tower from the 11th century, which was incorporated into the defensive system in the face of the danger posed by the Muslim invasion.