The Castle of San Terenzo is a fortification that stands in a dominant position on the seaside village of San Terenzo, a hamlet of Lerici, in the Gulf of the Poets. The current Castle was probably built in the fifteenth century by the inhabitants of the small village in order to protect themselves against the raids of Saracen pirates, the same 'Turks' from which takes its name from the cave that opens into the rocky promontory on which the castle. The building can be inscribed among the military works of the great defensive system developed by the Genoese Republic in the Gulf of La Spezia between the end of the sixteenth and the beginning of the seventeenth century, offshoot of the most imposing fortress of Lerici, now accessible by foot from the Castle along the picturesque promenade. Between the nineteenth and twentieth centuries it was transformed into barracks for sailors, soldiers and guard of finance and is used as a photoelectric station with lots of military personnel responsible for security and defense of the Gulf. Today it has abandoned its original military strategic function and is home to exhibitions and cultural events.