1-155-763 - Ann Ronan Picture Library/Heritage-Images

The Duomo, Florence, Italy. View of Brunelleschi's Basilica of Santa Maria del Fiore, commonly known as the Duomo, the cathedral church of the archdiocese of Florence. It was originally designed to be the largest Catholic church in the world, but the design was later scaled down. Work began in 1296, but proceeded erratically until, by 1418, only the dome, for which the cathedral is most famous, remained incomplete. The dome, built to a revolutionary octagonal design by Filippo Brunelleschi, was completed in 1436.