Named after the city's patron saint, work commenced on the basilica in 1392 but, for political reasons, was never finished. Originally intended to be larger than the first St Peter's in Rome, San Petronio was effectively truncated by the papacy, which decreed it could not be larger than St Peter's and that much of the land should be used for a university.

The facade is incomplete and if you walk along Via dell'Archiginnasio, on the eastern side of the basilica, you can see semi-constructed apses poking out oddly. Yet despite the papal interdiction, the basilica is still the fifth-largest in the world and an example of Gothic-style architecture at its best.

The central doorway, by sculptor Jacopo della Quercia, dates from 1425 and has exquisite carvings of scenes from the Old and New Testament and a beautiful Madonna and Child. The chapels inside contain frescos by Giovanni da Modena and Jacopo di Paolo.

One of the most interesting things about the cathedral is the giant sundial inside. It was an important element in the formation of the modern calendar.

The Basilica di Santo Stefano is a group of four churches remaining from an original seven. The triangular piazza before the basilica is on the swish Via Santo Stefano, a residential area for Bologna's wealthy, lined with the elegant facades of their palazzi.

On the right stands the 11th-century Romanesque Chiesa del Crocefisso (Crucifix) and the octagonal Chiesa del Santo Sepolcro (Holy Sepulchre), with a shape suggesting it started life as a baptistry. The Chiesa del Crocefisso houses the bones of San Petronio. Legend has it that the basin in the small courtyard is the one in which Pontius Pilate washed his hands after he condemned Christ to death. In actual fact it's an 8th-century Lombard artefact.