The tower spans three floors and stands 20 meters high in the historic center. It is a remnant of the ancient castle (10th–11th centuries). The Guevara family, counts of Potenza, built it and used it as a defensive lookout point. Later, a fortress was constructed to protect the residents of the historic city center. Eventually, it was donated to the Capuchin order, who converted it into a church and monastery. Another role of the observers was to monitor the rise of the Basento River, which flows beneath the city.