The secret underground passages sketched in Leonardo da Vinci’s notebooks have finally been found — beneath Milan’s Sforza Castle.
A team from the Polytechnic University of Milan, working with the Sforza Castle administration and engineering firm Codevintec Italiana, made the discovery using laser scanning, ground-penetrating radar, GPS, and photogrammetry to build a virtual 3D model from photographs.
Sforza Castle
What Did the Researchers Report?
Construction of Sforza Castle, in the heart of Milan, began in the mid-1300s. Over the centuries it was expanded, altered, and partly destroyed. Today only about one-sixth of the original structure remains, Live Science reports.
Around 1495, Duke Ludovico Sforza hired Leonardo da Vinci and other artists to decorate the castle’s walls and ceilings. During that time Leonardo sketched underground labyrinths in his notebook — drawings that researchers believe depict military passages.
Drawing of the Castle by Leonardo da Vinci
“Leonardo da Vinci knew a great deal about the military structures and defense systems of his time. His drawing shows the main body of the castle, as well as numerous passages,” said Francesca Biolo, the study’s lead author and an architectural history expert who has been searching for Leonardo’s tunnels as part of her dissertation project.
Biolo and her team focused specifically on the castle’s underground spaces. They wanted to determine whether inaccessible, previously unknown passages existed beneath the ancient structure.
“The results were more significant and intriguing than we expected. We discovered rooms on the second underground level and an additional passage that runs parallel to the known tunnel,” Biolo said.
She added that more passages likely exist beneath Sforza Castle, but excavations can’t be carried out there.
