Castelsardo is a picturesque town that stands on the sea, and the sea itself has marked its history. The town was used as a defensive stronghold and strategic control point. The ancient village still retains its medieval stronghold structure, with imposing ramparts, steep stairs and narrow streets.
At the top of the plateau stands the fortress of the Doria Castle, which houses the Museum of Mediterranean weaving.
A short distance from the castle, the 14th-century Cathedral of St. Anthony Abbot overlooks the sea, with a distinctive bell tower covered in colored majolica tiles. On the slopes of the castle stands the Church of Santa Maria delle Grazie, dating from medieval times, which preserves the wooden Crucifix of the Black Christ, dating from the 14th century.? Near the locality Multeddu stands the Elephant Rock, of dark trachyte entirely sculpted by the wind, which houses several domus de janas. This area has been inhabited since the Nuragic period: the remains of the Paddaggiu nuraghe remain from this presence. Of archaeological interest is the Monte Ossoni complex, which features a prehistoric village defended by imposing walls.
