The Church of SS. Gregorio e Siro was raised in the city centre between 1532 and 1535 by Tibaldo Tibaldi and Giovanni Antonio from Milan. In 1780 the façade and the arches were rebuilt by Angelo Venturoli because the church had been partly ruined by a particularly aggressive earthquake.
On the façade of the building there is the emblem representing the Ghisilieri family who had been living here until 1445. In 1532 a church was built next to the original building and the family tower was turned into a bell tower.
The church is plain outside but full of works of art inside: there are some great paintings by Camillo Procaccini, Lucio Massari, Calvart, Calvi and Carracci and the grave of a famous Bolognese man: the physician and biologist Marcello Mapighi.