Yes, there are hidden passageways in Milan Cathedral. Located behind the apse of the cathedral is a secret room called the Tesoro (Treasury). This room can only be accessed by a hidden door located in the wall which leads to a narrow stairway. The stairs descend into an underground tunnel that connects to other parts of the cathedral complex.
The staircase leads to an old chapel known as San Giovanni al Monte and also has access to some of Milan’s oldest catacombs. There is also another passage known as “the path of death” which runs underneath Milan Cathedral and dates back to Medieval times. This secret route was used by people during times of war or crisis and provided an escape route out of the city if needed.
There is another entrance located at one end of the Duomo di Milano which leads directly into a crypt beneath it containing several tombs from centuries past. All these hidden passageways provide evidence that much more than meets the eye lies within this majestic structure.