Basilica di San Petronio
Basilica di San Petronio features on the Gingerguide audio walk through Bologna. Give it roughly ~60 min: enough to look, hear a two to three minute story on the spot, and ask the AI guide whatever the story leaves open.
- Type religious
- Suggested visit ~60 min
- Bologna Bologna guide
About Basilica di San Petronio
The world's fifth-largest church, begun in 1390, with a famously unfinished marble façade and a colossal gnomonic line inside used as a solar observatory.
The Basilica di San Petronio is the dominant monument of Piazza Maggiore and the civic church of Bologna, dedicated to the city's patron saint, Petronius. Construction began in 1390 under the architect Antonio di Vincenzo. At 132 metres long and 60 metres wide, it is the fifth-largest church in the world. The famous unfinished façade, half marble, half bare brick, became a symbol of Bologna's perpetual conflict between ambition and resources. Inside, the church is breathtaking: enormous Gothic vaulting, a length of 132 metres, and an extraordinary treasure, the world's largest indoor astronomical instrument. This is the meridian line, a gnomonic line laid out in 1655 by Giovanni Domenico Cassini. A small hole in the roof allows a beam of sunlight to fall on the floor, marking the date and time with perfect precision. Charles V was crowned Holy Roman Emperor here in 1530, making this church the scene of one of the most significant events in European history.
Did you know? The Cassini Meridian Line inside, built in 1655, is the largest indoor sundial in the world and was used to calculate the speed of light.
How long is a visit to Basilica di San Petronio?
Set aside roughly ~60 min for Basilica di San Petronio. That covers a good look and the narrated story, and because you set the pace you can always stay on.
Is Basilica di San Petronio worth your time?
Basilica di San Petronio is among the 22 narrated highlights the Gingerguide team chose for Bologna, so it is worth a look. Hear the story for the context, then ask the AI guide for anything more.
Nearby stops in Bologna
Hear the story of Basilica di San Petronio
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