Visit the Basilica of San Petronio
Bologna, Italy
San Petronio dominates Piazza Maggiore with a façade whose unfinished brickwork is as distinctive as its marble lower section. Inside, the scale opens out into three naves and a series of chapels, with Cassini’s long meridian line adding an unexpected astronomical detail. Visit slowly enough to notice the contrast between the monumental space and individual works of art. General admission is free, while selected chapels require a separate ticket; check arrangements around religious services.