Florence’s fortresslike town hall was built from 1299 to 1302 on the designs of Arnolfo di Cambio, Gothic master builder of the city. The palace was home to the various Florentine republican governments (and is today to the municipal government). Cosimo I and his ducal Medici family moved to the palazzo in 1540 and engaged in massive redecoration. Michelozzo’s 1453 courtyard was left architecturally intact but frescoed by Vasari with scenes of Austrian cities to celebrate the 1565 marriage of Francesco de’ Medici and Joanna of Austria.

The grand staircase leads up to the Sala dei Cinquecento, named for the 500-man assembly that met here in the pre-Medici days of the Florentine Republic, and site of the greatest fresco cycle that ever wasn’t. Leonardo da Vinci was commissioned in 1503–05 to paint one long wall with a battle scene celebrating a Florentine victory at the 1440 Battle of Anghiari. He was always trying new methods and materials and decided to mix wax into his pigments. Leonardo had finished painting part of the wall, but it wasn’t drying fast enough, so he brought in braziers stoked with hot coals to try to hurry the process. As others watched in horror, the wax in the fresco melted under the intense heat and the colors ran down the walls to puddle on the floor. The search for whatever remains of his work continues, and some hope was provided in 2012 with the discovery of pigments used by Leonardo, in a cavity behind the current wall.

Michelangelo never even got past making the preparatory drawings for the fresco he was supposed to paint on the opposite wall—Pope Julius II called him to Rome to paint the Sistine Chapel. Eventually, the bare walls were covered by Vasari and assistants from 1563 to 1565 with subservient frescoes exalting Cosimo I and the military victories of his regime, against Pisa (on the near wall) and Siena (far wall). Opposite the door you enter, is Michelangelo’s statue of “Victory”, carved from 1533 to 1534 for Julius II's tomb but later donated to the Medici.

The first series of rooms on the second floor is the Quartiere degli Elementi, frescoed with allegories and mythological characters, again by Vasari. Crossing the balcony overlooking the Sala dei Cinquecento, you enter the Apartments of Eleonora di Toledo, decorated for Cosimo’s Spanish wife. Her small private chapel is a masterpiece of mid-16th-century painting by Bronzino. Farther on, under the coffered ceiling of the Sala dei Gigli, are Domenico Ghirlandaio’s fresco of “St. Zenobius Enthroned” with figures from Republican and Imperial Rome; and Donatello’s original “Judith and Holofernes” bronze (1455), one of his last works. In the palace basement are the Scavi del Teatro Romano, remnants of Roman Florentia’s theater, upon which the medieval palace was built, with remains of the walls and an intact paved street.

Visitors can also climb the Torre di Arnolfo, the palace’s crenellated tower. If you can bear the small spaces and 418 steps, the views are grand. The 95m (312-ft.) Torre is accessed on a separate ticket, and is closed during high winds or rain; the minimum age to climb it is 6, and children ages 17 and under must be accompanied by an adult.