The various rooms of the underground Priamàr were built throughout the life of the fortress between 1542 and 1943 and belong to different types: the large 16th-century tunnels, almost all of which were closed and walled up in the 17th century; the narrow connecting walkways dating back to 1683; the small counter-mine tunnels; the large rooms below the late 17th-century ramparts; the two cisterns and connecting tunnels of the Maschio and the Citadel; the sorties leading to the sea or the large outer moat; and finally, the large air-raid shelters from the Second World War.
The guided visit starts in front of the Civic Archaeological and City Museum; visitors will discover the underground passages of the Fortress with our archaeologists: they will follow the four underground routes of St. Bernard, St. Francis, St. Catherine, and Holy Conception.