Known locally as il Duomo, because of its enormous crowning dome, Florence's great cathedral ironically remained open to the elements for its first 100 years, until Filippo Brunelleschi came along. Santa Maria del Fiore was then one of the largest cathedrals in the world, later dwarfed only by Rome's St Peter's and London's St Paul's. Traditionally empty of pews, up to 10,000 people could congregate freely in the cathedral's vast interior. On Easter Sunday 1478, the Duomo was the site of the city's most infamous murder - Giuliano de'Medici was brutally stabbed to death in front of the congregation. Just 15 years later thousands of citizens gathered to hear the terrifying sermons of Savonarola, which Michelangelo claimed he could still hear ringing in his ears many years later.