The various rooms of the underground Priamàr were built over the entire lifespan of the Fortress, between 1542 and 1943, and fall into different categories: the large 16th-century galleries, almost all of which were closed off and walled up in the 17th century; the narrow connecting passageways dating from 1683; the small counter-mine galleries; the large chambers beneath the ramparts from the late 17th century; the two cisterns and the connecting galleries of the Keep and the Citadel; the posterns that led to the sea or the large outer moat; and, finally, the large air-raid shelter galleries from World War II.
The guided tour starts in front of the Municipal Archaeological and City Museum; accompanied by our archaeologists, visitors will explore the Fortress's underground areas: they will follow the four underground routes of San Bernardo, San Francesco, Santa Caterina, and Santissima Concezione.