The cathedral is the centrepiece of the Campo dei Miracoli and the building that taught all of Tuscany what a Romanesque church could be. Striped marble cladding, four tiers of blind arcades on the facade, a great rose window, and bronze doors cast in Florence in 1602 after the originals burned. Inside the space is calmer than the exterior promises: a flat coffered ceiling, hanging Galileo lamp (the one whose swing supposedly inspired his theory of the pendulum, though the dates don't quite work out), and Pisano's pulpit on the north side.
The cathedral is free to enter but you need a timed ticket from the Opera del Duomo office or website to control crowd flow. The mosaic of Christ in the apse, finished in 1302, is the only major work in the cathedral by an artist with a name attached — Cimabue, who died on the scaffolding before completing it.