Why go
The outside reveals the audacity of the cathedral's design. In 1367 Florence chose a model that rejected the flying buttresses common in northern Gothic building and instead imagined an immense dome on an octagonal drum. Brunelleschi later made that idea buildable with a structure of inner and outer shells. Seeing the drum and dome together makes the engineering problem visible from the piazza.
What to look for
- Read the octagonal drum as the base for a dome designed without external flying buttresses.
- Compare the dome's protective outer shell with the structural inner shell described in the design.
- Notice how the Renaissance dome rises above a Gothic cathedral body.
Useful to know
- Step back into Piazza del Duomo to see the drum, dome and cathedral body as one construction problem.
- Compare the exterior first, then look for the dome frescoes from inside if cathedral access is available.