Puerto Rico, for some years now, has been distinguished by the presence of an archaeological unicum that, to date, finds no comparison in the Western Mediterranean. The monument, located at Punta Su Nuraghe, was always thought to be a nuraghe, but the full archaeological excavation uncovered a cylindrical tower made of large shaped granite blocks, filled with stones and earth, lacking access and surrounded by a lower ring of stones and earth, built in the Punic age (late 4th-mid 3rd century B.C.) and used until the Augustan age. This was a tower for warning of dangers from the sea, which were signaled by lighting fires on the top of the tower; the signal was relayed back toward the Punic city of Olbia from a similar installation located on the hills separating the orographic basin of Cugnana from that of the city.
