Alghero is the most characterful town on Sardinia's northwest coast, a walled medieval port with a history that sets it apart from the rest of the island. Conquered by Aragon in 1354, it was repopulated with Catalan settlers and remained a Catalan-speaking enclave for centuries. A variant of the language — Algherese — is still spoken by some residents, street signs appear in both Italian and Catalan, and the architecture of the old town is unmistakably Catalan Gothic.
The old town occupies a small promontory enclosed by 16th-century walls and seven defensive towers. Walking the full circuit of the bastioni takes about 45 minutes and gives sweeping views over the bay. Inside, the Cathedral of Santa Maria, the Church of San Francesco with its Romanesque cloister, and the Palazzo d'Albis on Piazza Civica give a concentrated taste of the Catalan period. The port at the foot of the walls is a lively starting point for boat trips north to Neptune's Grotto at Capo Caccia — a 4 km sea cave with one of the most spectacular interiors in the Mediterranean.
The surrounding coast is protected as a marine reserve, and the waters around Capo Caccia are excellent for diving. Alghero is also well known for its red coral, historically harvested in these waters; coral jewellery is widely sold in the old town.