Il Duomo (Florence Cathedral of Santa Maria dei Fiori)
“Designed originally in 1296 by Arnolfo di Cambio, Florence's Duomo was actually the work of several architects, who overcame enormous technical challenges to design what is probably the central achievement of Renaissance architecture. Finally consecrated in 1436, the cathedral boasts Filippo Brunelleschi's enormous octagonal dome (the largest in the world when it was built and now the very symbol of Florence), whose interior features an enormous "Last Judgment" fresco by Vasari and Federico Zuccari; stained-glass windows by Lorenzo Ghiberti; and Paolo Uccello's huge clock in the entrance wall. The cathedral's red, white, and green marble facade was a late addition in the 19th century. To complete your trip, visit the piazza's other two landmarks: the baptistery, with its famous bronze "Doors of Paradise" by Ghiberti, and Giotto's slender bell tower, with a view of Renaissance Florence from the top of its 414 steps.
(1000 Places to See Before You Die)”