Fodor's Expert Review Basilica di San Petronio

Construction on this vast cathedral began in 1390; and the work still isn't finished more than 600 years later. Above the center of the door is a Madonna and Child flanked by Saints Ambrose and Petronius, the city's patrons. Michelangelo, Giulio Romano, and Andrea Palladio (among others), submitted designs for the facade, which were all eventually rejected. The Bolognesi had planned an even bigger church but had to tone down construction when the university seat was established next door in 1561. The most important art in the church is in the fourth chapel on the left: these frescoes by Giovanni di Modena date to 1410–15.