Behind the cathedral, on the east side, is a museum most visitors march straight past on their way to the dome climb. Don't. This is the Museo dell'Opera del Duomo — the museum of the cathedral works — and it's where all the real things went. Nearly everything you've photographed outside today is a copy. The originals are in here, pulled indoors over the years to save them from weather, pollution, and the occasional river.
The actual Gates of Paradise are in this building — Ghiberti's real gold doors, the ones the flood tore apart, cleaned and reassembled panel by panel over fifty years, sealed now behind glass in a room kept at a steady temperature, breathing filtered air. The copy bolted to the Baptistery takes the tourists and the sunlight. The original finally gets to rest.
But the object that stops people is a wooden dome sitting quietly in a case: Brunelleschi's own model. To win the job, and to show the masons what he actually meant, he built scale models of the thing he would
n't describe in words. What survives lets you see the double shell in cross-section, the herringbone coursing, the ribs — the entire secret logic he refused to write down, rendered in miniature by his own hand. The man who left almost no drawings left you a model instead. He thought in three dimensions, in wood and brick and rope, not on paper — he'd build a working model and let it argue for itse
