The most notable building in the historic centre is, without a doubt, the Church and Fortress of Sant Bertomeu, its construction dating from the 14th century to the 16th century, with expansions in the 18th and 19th centuries. The main structure falls within the Isabeline Gothic style. In 1931, it was declared a National Artistic Monument due to its importance and significance.

The history of the church begins in 1304 with the construction of the current presbytery, but the population growth and attacks from Barbary pirates from the 15th century onwards made it advisable to enlarge the fortress. Thus, in 1513, work began under the direction of the Navarrese master Domingo Urteaga. It is a large Gothic nave, topped by an apse, with three chapels on each side framed by buttresses.

Later on, several dependencies were added to the sides of the apse. On the north side, at the junction between the apse and the nave, there is the bell tower completed in the 17th century, also used as a watchtower. The ceiling is composed of cross vaults and, above the chapels, there is a gallery or triforium with open arches facing the interior of the nave and large windows on the outside for defensive purposes.

The main construction material is rough stone and decorative elements are scarce on the interior. The ornamental architectural elements on the exterior are also modest, where heraldic shields stand out above the access doors, vegetal decorations on the impost levels, thistle leaves and balls on the portals.

The ensemble is crowned with battlements and features arrow slits, openings for mortars, and two balconies above the doors and other elements that existed in the past so as to form a railing on the upper part of the building. It perfectly fulfilled its two objectives: to meet the religious needs of the village and to defend the population against attacks from Barbary pirates. In the underground part of the current pavement, around the church, there is an unexplored set of crypts and burial jars yet to be uncovered, probably dating back to the 16th century.