Basilica di San Petronio

This is the church everyone thinks is the Cathedral, but remember: it is not. It was built by the Comune (the city government), not the Bishop, making it a symbol of Bologna's civic power. It is dedicated to the city's patron saint, Petronius. As mentioned in the Piazza Maggiore review, the façade is famously split. The bottom is elaborate pink and white marble (designed to rival the greatest churches in Italy), and the top is rough, naked brown brick. Construction started in 1390 and dragged on for centuries. Legend says the Pope intervened to stop it from becoming larger than St. Peter’s in Rome, diverting the funds to the Archiginnasio nearby. The result is a uniquely "Bolognese" aesthetic—grand ambitions meeting practical reality. Embedded in the floor of the left aisle is the longest indoor meridian line in the world (66.8 meters), calculated by the astronomer Giovanni Domenico Cassini in 1655. There is a small hole in the roof (gnomon). At exactly solar noon (around 12:15–12:30 PM depending on the season and Daylight Savings), a beam of sunlight hits the floor, indicating the exact date. It proved that the Earth orbits the sun elliptically, not in a perfect circle.

The Basilica di San Petronio is absolutely breathtaking and well worth a visit if you’re in Bologna. We went over the weekend and were pleasantly surprised that there was no wait to enter. Even though it was busy inside, the sheer size of the basilica meant we could explore at our own pace and really soak in the atmosphere. The history here is incredible — construction began in the late 14th century, and it was originally intended to be even larger than St. Peter’s in Rome. Today, it remains one of the largest brick churches in the world, with an interior that feels both grand and peaceful. One tip: they are strict about the dress code, so be sure to cover your shoulders and avoid shorts or skirts cut too high above the knees. A small effort for such an unforgettable experience!

Located in the heart of Piazza Maggiore, Bologna's Basilica of San Petronio is a testament to unfulfilled ambition and striking beauty. Its most distinctive feature is the unfinished façade—the lower half a masterpiece of intricate marble reliefs, while the upper half remains raw brick, a stark reminder of papal interference that halted its construction. Inside, the vast, echoing space is a stunning example of Italian Gothic architecture. The nave soars to an incredible height, flanked by 22 chapels, each a treasure trove of art. Don't miss the Bolognini Chapel, with its vivid frescoes of Heaven and Hell, a controversial masterpiece by Giovanni da Modena. The sheer scale and rich detail of the interior make it a captivating and deeply historical space, revealing Bologna's unique cultural and religious identity. CASSINI'S MERIDIAN Embedded into the floor is, a celestial wonder which unfolds beneath my feet. Not a grand dome or a soaring fresco, but a precise, 67-meter-long line of brass and marble—the Cassini Meridian. This isn't just a decoration; it's a monument to scientific genius, a grand solar observatory in stone. As I trace its path with my gaze, I imagine Giovanni Domenico Cassini and his team, hunched over their instruments in 1655, meticulously calculating the sun's altitude at noon. The sliver of sunlight piercing the basilica's vaulted ceiling, a golden messenger from the heavens, projects a perfect ellipse of light onto the meridian, its position a testament to the changing seasons and the Earth's tilted axis. This line, etched into the basilica's heart, is a testament to the harmony between faith and reason. It's a reminder that even within the walls of a sacred space, humanity's quest for knowledge of the cosmos can find its place, illuminating both the divine and the scientific in a single, brilliant beam.

Cathedral in the heart of Bologna city center. If you're here do stop by! Make sure you are dressed appropriately, while its a free visit they do ask that you respect the dress code with covered knees and covered shoulders. It's rich in history and has various chapels worth visiting. The chapel holding the last judgement was closed for us but typically 5€ to visit. Again because it holds the last judgements painting. Would've loved to see it up close. But dont let that stop you from seeing the entire church and each chapel The chapels hold different ornaments and beautiful paintings, take you're time. Translate the plaques research the history its always worth it. Take time to enjoy the church and enjoy all the history inside. And dont forget to look down the tiles/floor holds secrets too!

Basilica with tall ceiling. It had some Christmas decorations inside to commemorate the birth of Christ. You can walk and admire the inside of the church. Enter by the front and exit at the back of the church. Entrance is free.

A very interesting church in the central square of Bologna, ( and definitely had more character than the cathedral). Because of it's location, and the more of I heard about it from other tours and events going on in the area, I ended up visiting this church 3 times within 3 days. However, every time I visited, I learned something new, such as how the built sundials work, or something about one of the many chapels in the building. There were soldiers at the front, which was a little unusual for other churches, but it seemed to cause no issues when visiting.

The Basilica di San Petronio is truly impressive. Its unfinished façade gives it a unique charm, and once you step inside, the vast space and beautiful light are striking. The frescoes and artwork make you feel like you’re walking through living history. The atmosphere is calm and majestic, and every corner reflects the soul of old Bologna. A visit that’s absolutely worth it, especially if you enjoy historic sites with depth and character.

The Basilica di San Petronio is more than just a church, it’s one of the most awe-inspiring spaces in Bologna, blending massive scale, scientific ingenuity, and quiet grandeur. It’s the sixth-largest church in Europe, and standing beneath its soaring vaults, you feel every bit of that scale. What made our visit truly special was witnessing the sunbeam cross the enormous meridian line, a sundial built into the floor that still tracks solar noon with remarkable precision. It was a quiet moment, but deeply powerful; like watching time and faith align in a single ray of light. What many don’t realize is that this basilica was originally intended to be even larger than St. Peter’s in Rome, until the Vatican halted its expansion. That ambition still lingers in the unfinished façade and colossal proportions. Every chapel feels like its own world, and the blend of Gothic structure with Renaissance detail invites you to linger. San Petronio isn’t just a church; it’s a testament to Bologna’s boldness, intellect, and soul. If you’re lucky enough to catch the sundial in action, it’s a moment that stays with you.

Situated in Piazza Maggiore the imposing front face of the basilica stands out immediately, its half-brick, half-finished white and red marble lower half stark in contrast. The finished face of the cathedral is sparsely adorned compared to similar church buildings of the same period. Inside the soaring cream-colored vaulted ceilings also contrast with the terra-cotta column and archway edges, another reflection of the white and red colors of the city. The main apse ceiling appears modest and undecorated, though a few of the smaller chapel ceilings exemplify the colorful murals that may have been intended for the total ceiling once finished. Interestingly enough when looking up some history this basilica was meant to serve as a more of a civil center rather than purely religious building. Entry is free (donations suggested) and no advance reservation is needed. When I came by on a Tuesday afternoon in April the church was finishing up a service, all the while allowing passersby to enter and visit, of course asking to maintain a respectful silence. Parishioners lit candles and prayed in front of the local patron saint as well as at individual chapels. Intriguing to get a glimpse into how different cultures interact in places of worship.

The Italian Gothic basilica is dedicated to Saint Petronius, who was the bishop of Bologna in the 5th century. A life size statue of him is in the basilica. It was built in 1390 and its main facade is still unfinished. The building was transferred from the city to the diocese in 1929 and was consecrated in 1954. 28,000 people can fit inside, it is enormous. The altar contains a 15th-century wooden crucifix. At the back, a fresco of the Madonna and cartoons. The ornate ciborium of the main altar was built in 1547. The 15th century wooden choir was completed by Agostino de 'Marchi. The vaulting and decoration of the central nave is by Girolamo Rainaldi, who completed it in 1646. The nave contains twenty-two side chapels each more ornate than the next. In 2002 five Al Quads terrorists were arrested, they were planning to blow up the basilica. They were angry a fresco depicts Mohammed in hell being devoured by demons.

The huge, Gothic Basilica of San Petronio was originally supposed to be bigger than St. Peter's in Vatican City, but Pope Pio IV apparently commissioned an extension to the university next door, and put a stop to the grand plans. It's still incredibly impressive, though - the façade is half marble, half exposed brick; and inside, you'll find frescoes, bronze busts and the world's biggest sun dial. Dedicated to Saint Petronius who is actually the patron saint of Bologna, the church has a Gothic design and it is noted for both its sheer size and its unfinished front facade. Inside, the church feels truly enormous - the brick columns seem to go on forever and the main altar captures your attention as you walk down the central aisle. This is a church not to be missed.

So, it was just our luck that the same day that we rolled into Bologna to live it up was also the day of San Petronio! We got to attend a service at this very crowded basilica honoring the saint along with the rest of the people of Bologna. The piazza in front of the church is a kind of gathering point for all people, local and tourists, with several sitting on the steps and enjoying the free wifi spot. Since it was the saint's day and admission was free, we decided to go in to check everything out. The basilica here is standard as far as several hundred year old Italian basilicas go. And by standard, I mean that it is devastatingly beautiful. This is not as gothic as the basilica in Firenze, but more gilded that the other cathedral on the other side of Bologna by the university. The paintings and frescoes here are very well maintained and wonderful representations of art from the era they church was built in. I will also add that the acoustics here are very good, even without microphones. If you're stopping through Bologna, you should check this place out. It's free, takes up maybe 30 minutes of your time, and is a very well maintained piece of cultural importance.

Pretty awesome thing. I believe it is the fifth largest church in the world. It's free and there's not much to it - I believe it is simply one HUGE room. You really cannot miss it, and should not miss it. Doesn't cost anything and doesn't take much time. You don't even have to put it on your list because you will inevitably pass it.

This magnificent building stands in Piazza Maggiore and is the fifth largest church in the world! It would have been the largest, outdoing even St Peters in Rome, if Pope Pius 1V hadn't put his foot down. It was begun in the 14th century and work continued for hundreds of years. The 17th century vaults and pillars of the central nave are beautiful and there are many fine carvings, stained glass windows and paintings to see, particularly 'Madonna with Saints' by Lorenzo Costa. Well worth a visit.