Medici Fortress
The current fortress is a massive polygonal contruction included perfectly in the town walls. It was built under the direction of Antonio da Sangallo (the Younger) and Nanni Unghero between 1538 and 1560 on the site of the old medieval cittadella, which had been razed to the ground because it was in the way of the line of fire of the cannons, and englobed most of the trapezoid Forte designed by Giuliano and Antonio (the Elder) da Sangallo at the beginning of the 16th century.