Archaeologists Blown Away After Finding Secret Tunnels That Da Vinci Had Drawn Over 500 Years Ago Researchers from the Polytechnic Institute of Milan visited the site of Italy’s famed Sforza Castle as part of a doctoral thesis and conducted a technological study.

An underground tunnel network long rumored thanks to drawings by Leonardo da Vinci under Milan’s Sforza Castle are proven to exist. Ground-penetrating radar and laser scanning revealed that the historic passages made famous by a Leonardo da Vinci drawing is just one of multiple tunnel sections.

As per the Politecnico di Milano, the investigation has “revealed the presence of numerous underground passages under the Sforza Castle.”

For centuries, whispers of hidden tunnels beneath Milan’s iconic Sforza Castle have intrigued historians and treasure hunters alike.