10 fascinating facts about Milan Cathedral you might not know

Milan Cathedral is a magnificent Gothic masterpiece that dominates the heart of the Lombard capital, standing as an undisputed icon of Italian architecture and culture.

Yet behind its towering spires and intricately decorated façade lie secrets and curiosities that often go unnoticed by visitors. Here are ten fascinating facts you may not have known about Milan Cathedral.

The archaeological excavations beneath the Duomo

To uncover the first curiosity about Milan Cathedral, we must step back in time to ancient Rome, when the city was known as Mediolanum. At the site now occupied by the Cathedral, there once stood two early Christian basilicas and a baptistery: the ancient Basilica of Santa Maria Maggiore, the Basilica of Santa Tecla, and the Baptistery of San Giovanni alle Fonti.

The latter, a pioneering example of octagonal architecture from the early Christian era, was where Saint Ambrose baptised Saint Augustine on Easter Eve in 397. Traces of the Basilica of Santa Tecla and the distinctive octagonal shape of the baptistery can still be seen today in the Duomo’s archaeological section, offering a tangible link to a glorious and spiritually significant past.

A construction spanning six centuries

One of the most fascinating facts about Milan Cathedral is that its construction took an astonishingly long time. It is no coincidence that Milanese people use the phrase “”like the Fabbrica del Duomo”” to describe an undertaking that drags on indefinitely, seemingly without ever reaching completion.

The cathedral’s official construction began in 1386, yet it was only finally completed in the 19th century, thanks to the tireless efforts of thousands of artists, sculptors, and craftsmen from across the world.

Italy’s largest organ

Few people know that Milan Cathedral is home to Italy’s largest organ. Located at the high altar, this extraordinary instrument boasts 15,800 pipes and four organ cases.

Some of the pipes soar to heights of over nine metres, while others are so tiny they measure just a few centimetres. The magnificent panels surrounding the organ are true masterpieces, painted with scenes from the Old and New Testaments, adding an air of sacredness and grandeur to the already breathtaking cathedral.

Zodiac signs on the floor

Upon stepping into the vast cathedral, visitors will notice a sundial engraved in the floor, stretching across the width of the nave from right to left. Along its path, marble tiles bear engravings of the twelve zodiac signs.

Looking up at the vaulted ceiling of the first chapel on the right, a small hole can be seen. At solar noon, a ray of sunlight filters through this opening, illuminating the corresponding zodiac sign on the tile below, depending on the time of year.

This sundial, constructed in 1786 by astronomers from the Brera Astronomical Observatory, is periodically adjusted to account for shifts over time, including the gradual lowering of the floor caused by the construction of the metro line beneath the cathedral.

The crucifixion nail

Another fascinating detail about Milan Cathedral concerns a very special nail. In the central nave, if you look up towards the ceiling of the apse, you will spot a tabernacle positioned 40 metres high. This tabernacle houses a relic of inestimable value: the Holy Nail, believed to be one of the nails used in the crucifixion of Christ, according to tradition.

This precious relic is removed from its reliquary and brought to the cathedral’s altar just once a year, in September, during one of the most evocative and mysterious ceremonies of Milanese tradition: the Rite of the Nivola. As part of this ritual, a cloud-shaped ‘elevator’ is used to transport the relic, creating a solemn and deeply atmospheric moment within the cathedral.

Saffron in the stained glass windows

Among the many little-known curiosities about Milan Cathedral is a fascinating story linked to its magnificent stained glass windows. The cathedral boasts 52 of these majestic, vividly coloured windows, which not only embellish the interior but also served an educational purpose: through biblical imagery, even those who could not read were able to learn the sacred stories.

But there is more. Surprisingly, the origins of Milan’s iconic saffron risotto are said to be connected to these very windows. Historically, saffron was used to produce yellow-coloured glass, and legend has it that the apprentice of the Belgian master glassmaker Valerio da Fiandra (who was responsible for crafting the cathedral’s stained glass) decided to add saffron to a risotto dish during his master’s daughter’s wedding. This simple act is thought to have sparked a culinary tradition that has since become a symbol of Milanese cuisine.

The walkable roof

The terrace of Milan Cathedral attracts millions of visitors every year. By climbing its 251 steps or taking a quick lift ride, they can explore the cathedral’s vast 8,000-square-metre terraces, which form the walkable roof of the world’s largest Gothic cathedral.

Amidst the spires and thousands of intricately carved marble details, one feature stands out: on the spires facing the square, along the left-hand edge, two boxers are depicted in combat. These sculptures were created to honour the renowned Italian boxer Primo Carnera, celebrating his achievements in the world of boxing.

The self-cleaning façade

In the earliest colour photographs of Milan Cathedral, its façade appears almost completely black. This is because Piazza Duomo looked very different from how we know it today: all forms of public and private transport were allowed to pass through, as pedestrianisation only took effect towards the late 1980s. As a result, the effects of air pollution were clearly visible on the cathedral’s exterior.

However, in the past decade, the façade has been treated with a natural material that, activated by sunlight, has the ability to self-clean and purify the air by breaking down fine particulate matter.

Milan Cathedral once had a bell tower

A lesser-known fact about Milan Cathedral is that it once had its own bell tower, positioned at its summit and likely dating back to the ancient Basilica of Santa Maria Maggiore. However, in 1866, concerns over structural safety led to its demolition.

Following its removal, there were discussions about constructing a new bell tower outside the main structure. One of the first architects to put forward such a proposal was Luca Beltrami, who suggested building it near the Manica Lunga of the Royal Palace (which no longer exists today). However, the project never came to fruition.

The true role of the Madonnina

For over two centuries, the Madonnina has stood proudly atop Milan Cathedral, watching over Piazza Duomo and the entire city. Positioned at a height of 108.5 metres, she is not only seen as a protector of Milan but also a guardian of the cathedral itself.

Alongside the statue, a decorative halberd serves a hidden yet essential function: it is, in fact, a lightning rod, designed to shield both the Madonnina and the cathedral from lightning strikes and harsh weather conditions.

Article translated by Agnese Giardini

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Curiosities

Travel

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