Alghero has eight surviving towers from its defensive walls and another eleven along the coast, strategically positioned opposite each other to transmit any signs of danger.
The most curious is the Tower of San Giacomo, which has an unusual octagonal shape, and the Tower of Maddalena with projecting machicolations for dropping boiling oil and water on enemies. Among the coastal ones, the most evocative is undoubtedly the Tower of Pegna, built on a promontory where coral fishermen worked, between Porto Conte Regional Park and Capo Caccia.