The whole area has been designated a UNESCO World Heritage Site since 1999.

The present-day gothic church, built in the 14th century, is dedicated to the Virgin Mary. The small nave has a vault supported by seven pairs of pillars that are attached to the side walls.

The church is surrounded by an oval precinct with 7-8 meter high mantle walls. The church and precinct are accessed via a vaulted gangway with portcullis on the western side.

On the sides there are four bastions oriented north, south, east, and west. The walls are equipped with battlements and machicolations that are supported by brackets on the outside.