Remains of towers located in strategic
positions, designed to control shores and coastal roads, still survive in Molise. These towers, which are visually connected with each other and with lookout
points, bear witness to an impressive defence system activated at the end of the 16th century in order to protect all the coasts of southern Italy
against attacks by sea, but also to control the production activities in the interior. The results, in truth, were not impressive, so these defences were soon
abandoned. The models adopted were simple (square towers with scarp and counterscarp, with a raised entrance accessible through a stair) and reproduced with few
modifications. The surviving towers on the Molisian coast are those of Petacciato and of Sinarca, while the tower built at the mouth of the river Trigno and the
tower of Campomarino have disappeared. They are all well documented in the report made by the Marquis of Celenza to the Viceroy of Naples (1594) and preserved
in the National Library of Paris.
In addition to these towers there are two artefacts which date back to different periods and have different structural characteristics, but which may have
contributed at some time to further strengthen the defences : the tower of Montebello, built on a hilltop two kilometres from the coast, and the Meridian tower
(cylindrical and tapered), which is the reference point for the intersection of the 15th meridian and the 42nd parallel.