San Petronio Basilica: a complete guide to visit the largest church in Bologna

San Petronio Basilica isn't only the biggest and one of the best churches in Bologna.
With its grand dimensions, artistic treasures, and unfinished façade, it tells a story of ambition, faith, and science that continues to captivate visitors.

Here’s everything you need to know to enjoy your visit.

San Petronio Basilica: A Giant Among Giants

Did you know that San Petronio is the fifth-largest Catholic church in the world?

Measuring 132 meters in length and 66 meters in width, its size alone is awe-inspiring.

Initially planned to surpass even St. Peter's Basilica in Rome (legend tells), it represents Bologna’s civic pride and ambition during the late Middle Ages.

The basilica’s construction began in 1390, under the direction of Antonio di Vincenzo, who envisioned it as a Gothic masterpiece.

Over the centuries, the project evolved through numerous hands, yet it remains unfinished, with its stark brick upper façade contrasting sharply with the marble-clad lower half.

The Facade of the Church: Many Stories in the Stone

The façade of San Petronio is a puzzle of marble and brick.

Artists like Baldassarre Peruzzi, Jacopo Barozzi (yes, the one behind Torta Barozzi Cake), and even Andrea Palladio proposed designs to complete it, but none came to fruition.

Adding to its fascinating history, in 1508, a bronze statue of Pope Julius II by Michelangelo once adorned the main gate. Sadly, it was destroyed, and the metal was repurposed for artillery.

Back to modern times, in 2020, modern architect Mario Cucinella suggested transforming it into a green façade filled with trees, sparking conversations about sustainability in historic architecture.

The Meridian Line of San Petronio: What's the Time, Please?

Once inside San Petronio Basilica, you can't ignore the stones you're walking on.

Take a look up to check a small hole in the roof allowing a beam of sunlight to fall onto the basilica’s marble floor, where zodiac signs mark the Sun’s position throughout the year.

This is the largest meridiana clock in the world, designed in 1655 by astronomer Giovanni Domenico Cassini.

The meridian line is not just an architectural curiosity but a scientific tool.

By observing the sunlight’s movement, Cassini was able to demonstrate the accuracy of the Gregorian calendar and measure time and seasons with extraordinary precision.

Walking along this line today, you’re not just admiring art—you’re witnessing a brilliant example of 17th-century science in action.

Mohammed in San Petronio: Not just Another Fresco

San Petronio Basilica seems huge and empty, but there's something to look for on the walls.

It's the Bolognini Chapel, adorned with frescoes by Giovanni da Modena.

These vivid paintings depict Hell, Purgatory, and Paradise, inspired by Dante Alighieri’s Divine Comedy. The detail and emotion in these works make them a must-see for any visitor.

If you search not far from the devil, you can find the prophet Mohammed - indicated by a Machomet inscription.
He is depicted naked at his feet, lying on the ground, with his body tortured by a horned demon who grabs him by the head and ties him with snakes.

To see this scene closely you'd have to pay a 5€ ticket.

Plan your visit: What to know Before Entering the Church

San Petronio Basilica is open to visitors year-round, with guided tours available to help you uncover its many secrets.

While entry is free, it’s best to avoid visiting during religious celebrations to respect the sacred atmosphere.

When planning your visit, remember to dress appropriately.
Although no one will stop you at the door, it’s important to be mindful that this is a place of worship for many, and showing respect is always appreciated.

[photos and credits foliamagazine.it and Alessio Vallero]