Topped by a fine 94m-high bell tower, this huge building dominates the square. Built between 1299 and 1314 to designs by Arnolfo de Cambio, this uncompromising Gothic structure was initially the seat of the Signoria. It became Cosimo I's residence in the 16C and was adapted by him for courtly life. The decor by Vasari, who worked here as decorator, architect and artist, dates from this period. The lavish and elegant Renaissance-style interior provides a striking contrast to the austere exterior.