Sperlonga’s watchtowers date back to 1500. The central tower, of which only a part survives in Via Giosa, dominates the town and its profile is drawn in today’s Municipality’s symbol.
The Truglia Tower stands on a rock of bare stone on the extreme tip of the Sperlonga promontory. Built in 1532 on the foundations of a pre-existing Roman watchtower, only two years later it was devastated by the hordes of Kaireddin Barbarossa. Rebuilt in 1611, when it housed a sergeant and a single soldier, already in 1623 it was again devastated by the Turks. It flourished only in the following century, when it was a safe lookout for the whole coast. From 1870 to 1969 it was used by the Guardia di Finanza. It is currently open to the public for most of the day. Inside, an information office managed and coordinated by Sperlonga Turismo.
Sperlonga’s coastal defense system was completed by the Torre del Nibbio and the Torre di Capovento, which rises about 3 km south of the town. Built on a spur of rock overlooking the sea in 1532, after various events, it served from 1820 as a customs post. After almost complete destruction, it has only recently been rebuilt again.