Dominating the Piazza Maggiore's southern flank, the Gothic Basilica di San Petronio is Bologna's greatest church. Dedicated to the city's patron saint and measuring 132m by 66m by 47m, it's the world's fifth-largest basilica. Surprisingly, though, it was never finished.
Basilica di Santo StefanoFrom the two leaning towers, head southeast along Via Santo Stefano for the Basilica di Santo Stefano, an atmospheric medieval religious complex. Originally there were seven churches - hence the basilica's nickname Sette Chiese - but only four remain. Entry to the Basilica di Santo Stefano is via the 11th-century Chiesa del Crocefisso, which houses the bones of San Petronio and leads through to the Chiesa del Santo Sepolcro. This austere octagonal structure probably started life as a baptistry.
Basilica Santuario della Madonna di San LucaAbout 3.5km southwest of the city centre, the hilltop Basilica Santuario della Madonna di San Luca houses a representation of the Virgin Mary, supposedly painted by St Luke and transported from the Middle East to Bologna in the 12th century. The 18th-century sanctuary is connected to the city walls by the world's longest portico, held aloft by 666 arches, beginning at Piazza di Porta Saragozza.