When Michelangelo went to work on St Peter's in Rome, he reportedly said: 'I go to build a greater dome, but not a fairer one'. One of the finest masterpieces of the Renaissance, the cupola crowning the Duomo is a feat of engineering and one that cannot be fully appreciated without climbing its 463 interior stone steps. It was built between 1420 and 1436 to a design by Filippo Brunelleschi, and is a staggering 91m high and 45.5m wide.
Taking his inspiration from Rome's Pantheon, Brunelleschi arrived at an innovative engineering solution of a distinctive octagonal shape of inner and outer concentric domes resting on the drum of the cathedral rather than the roof itself, allowing artisans to build from the ground up without needing a wooden support frame. Over four million bricks were used in the construction, all of them laid in consecutive rings in horizontal courses using a vertical herringbone pattern.
The climb up the spiral staircase is relatively steep, and should not be attempted if you are claustrophobic. Make sure to pause when you reach the balustrade at the base of the dome, which gives an aerial view of the octagonal coro (choir) of the cathedral below and the seven round stained-glass windows (by Donatello, Andrea del Castagno, Paolo Uccello and Lorenzo Ghiberti) that pierce the octagonal drum.
Look up and you'll see flamboyant late-16th-century frescoes by Giorgio Vasari and Federico Zuccari, depicting the Giudizio Universale (Last Judgement).
As you climb, snapshots of Florence can be spied through small windows. The final leg – a straight, somewhat hazardous flight up the curve of the inner dome – rewards with an unforgettable 360-degree panorama of one of Europe's most beautiful cities.
Buy tickets from the Duomo ticket office at Piazza San Giovanni 7, opposite the baptistry's northern entrance.
