Fortress of Santa Barbara:

TAn important example of military architecture built over the foundations of an earlier 14th-century stronghold, the Santa Barbara Fortress was built for Cosimo I de' Medici, grand-duke of Tuscany, who consolidated his power by promoting large-scale public works, mainly of a military nature. Designed by Nanni Unghero (1539), with construction work overseen by military architect Giovan Battista Bellucci, the structure consists of a central quadrangular block with ramparts at the corners and a moat, which was subsequently incorporated into new ramparts connected to the city walls, by Bernardo Buontalenti (1571). It was decommissioned in 1774 and later used as barracks, as a prison and as a recruitment centre. It is now preserved as a historical monument.