A Medici military building in the heart of Florence
Fortezza da Basso was built at the behest of Alessandro de' Medici not so much to defend the city after the Siege of Florence as to discourage new sieges and to make the Florentines understand who held the power, extinguishing any idea of a Republic, at the cost of resorting to the use of cannons, aimed at the city. The mighty walls of the Fortress draw an irregular pentagon and incorporate the ancient Porta a Faenza within the keep, which was part of the last circle of city walls, built in the thirteenth century. Inside, it contains the Monumental Quarters, hosting some of the oldest rooms of the Fortezza da Basso such as the Cannoniera, with its panoramic terrace, the Sala della Scherma, the Sala dell'Arco, the Sala delle Armi, the Sala delle Grotte in the large underground areas where the Mugnone river once flowed, the Sala Ottagonale with its vaulted roof and "herringbone" bricks, a technique previously used by Brunelleschi for the dome of the Cathedral of Santa Maria del Fiore. The Polveriera, now an elegant place, was once used as a storehouse for explosives and ammunition. Outside, it is surrounded by the Giardini del Vascone and the Giardino dei Cigni.
The military facility has been turned into an exhibition and trade show venue with the construction of the Spadolini Pavilion and the Cavaniglia Pavilion in steel and aluminum.