This former Greek acropolis dominates the city, boasting a perimeter wall which was strengthened by the Spanish under Charles V. Arriving at the castle via piazza Mazzini, you will see the Spanish fortifications, a Greek tower and medieval constructions before reaching the citadel which accommodates Saint Catherine's church, the archaeological sites, followed the chapel of the Addolorata n the Church of the Immaculate, finishing up with the cathedral dedicated to Saint-Bartholomew.