Originally in the Middle Ages, four towers were built to defend themselves from the Saracens, by order of the viceroy Don Pietro di Toledo: the Central Tower and the Torre del Nibbio, are today incorporated between the houses of the town, giving that perched and winding aspect that is a characteristic of Sperlonga.
The Truglia Tower with a quadrangular plan and sturdy lateral buttresses stands on the promontory at the entrance to the marina.
Erected on the ruins of a previous Roman tower, it was razed to the ground only two years later.
Rebuilt in 1611, it was again demolished by the Turks a few years later, to be put back on its feet the following century as a lookout post.
From 1870 to 1969 it hosted the Guardia di Finanza.
The Capovento Tower was also part of the defensive system, a few kilometers south of the town, on the overhang of the same name, also used as a customs post.