Alghero's old town occupies a small promontory between the harbour and the sea, enclosed by 16th-century walls and seven defensive towers. The street pattern is medieval — narrow, irregular, and aligned more by historical accident than design — and the buildings are still mostly the original stone houses, three or four storeys high, with iron balconies and ground-floor shops. Most of the centre is pedestrianised.
The main squares — Piazza Civica, Piazza Duomo, and the smaller Piazza Sulis — are easy reference points. Wander between them rather than aiming directly. The cathedral, the bishop's palace, the Palazzo d'Albis with its Catalan facade, and the small but lively coral and ceramics shops all sit within five minutes' walk of each other. Evenings are when the old town comes alive — the passeggiata along the seafront walls, with the lit-up cathedral tower as a backdrop, is one of the more romantic in Italy.