Walls, towers and gates Torre di Guardia historic building erected in 1716 at the behest of Pope Clement XI. The tower was used as an observatory for the sighting of pirates, who haunted the Adriatic at that time and threatened its populations. The building was built on what is a real natural 'elbow' that stretches out over the Adriatic Sea, and was, due to its wide view, a perfect spot of sight.