Defensive walls in Alghero, City walls in Alghero, Italy

The Defensive walls of Alghero are limestone structures that run along the Mediterranean coast, surrounding the old town with towers, bastions, and gates forming a complete protective ring. They enclose the historic center and can be viewed from multiple vantage points along their entire circuit.

These fortifications were built in the 16th century under Spanish rule to protect the coastal settlement from naval attacks and military threats. Later Italian rulers maintained and adapted them to suit changing defensive needs.

The sea-facing bastions carry the names of navigators: Cristoforo Colombo, Antonio Pigafetta, Ferdinando Magellano, Marco Polo and the Maddalena, starting from Piazza Sulis. Torre di Porta Terra was also called Torre degli ebrei because the Jewish community contributed to its construction, and a memorial to the fallen of both world wars is set into its walls.

The sea-facing bastions run from Piazza Sulis to the old hospital, and the restored walkway links up with the Lungomare Dante built in the 1950s. About 70% of the walls survive; the stretch between the Forte della Maddalena and the Torre de l'Esperó Rejal is gone. The landward walls were demolished from 1867, so the circuit is open on that side.

The Torre di San Giacomo is also called Torre dei Cani because it once housed a dog kennel; it has an octagonal plan and, despite 17th-century changes, keeps Catalan Gothic elements such as the niche by the main entrance and a spiral staircase leading down. The Torre di Sant'Elmo, dedicated to Saint Erasmus, patron of sailors, bears a relief of the Crown of Aragon's coat of arms on its exterior.