The bastion at the town’s seaward edge was built between the 14th and 17th centuries but owes its current look to an Austrian makeover in 1833. It's now used for film screenings on summer nights. Downstairs, a 15-minute video tells the story of Ottoman admiral Barbarossa wresting the fort from the Spanish in the 1539 Siege of Castelnuovo.
In the sea below, you can see the ruins of the Citadela, a Venetian-built fort that was the victim of a major earthquake that hit the coast in 1979.