Duomo · Piazza del Duomo
Brunelleschi built the world's largest dome without scaffolding — and kept his method secret
When Filippo Brunelleschi won the commission to dome Florence's cathedral in 1418, the hole in the roof had been open for 50 years because nobody knew how to close it. Brunelleschi invented new machines, new bricklaying patterns and a herringbone technique so revolutionary he refused to explain it to anyone — fearing his competitors would steal it. He died before seeing it completed. The dome remains the largest masonry dome ever built. Modern engineers still debate exactly how he did it.