Walls, towers and gates Torre di Cala d'Ostia The Tower of Cala d'Ostia was built in 1773. The tower played the defensive function against the Barbarian raids. In the years from 1807 to 1813 the tower was manned by 5 soldiers and after 1842 it was abandoned for a very long period until 2003, when it underwent restoration work.
Walls, towers and gates Torre Coltellazzo The Coltellazzo Tower was built in 1607 above the remains of the acropolis of Nora. The building was built by engineer Antonio Felice de Vincenti. The tower, also known as the tower of Sant'Efisio, has a truncated conical structure of about 11 meters high, built with limestone sandstone. At the center of the tower is a room which is supported by a central pillar.