Leonardo da Vinci’s genius extended beyond art and science—his military innovations shaped defensive strategies during the Renaissance.
Now, over 500 years later, researchers have uncovered mysterious tunnels beneath Milan’s medieval Sforza Castle, believed to match sketches drawn by da Vinci in 1495.
A Hidden Passage Beneath History
According to Digi24, the tunnels were likely designed as secret escape routes or defensive passageways for soldiers in the event of an invasion.
Their discovery was announced in January by researchers from Politecnico di Milano after a multi-year study from 2021 to 2023 aimed at digitally mapping the castle’s underground structures.
Francesca Biolo, an architect and researcher involved in the study, emphasized the significance of the find.
"Our discoveries remind us how deeply history is embedded in our cities," she said. Using non-invasive methods such as ground-penetrating radar and laser scanning, the team was able to reveal these long-lost passageways.
Da Vinci’s Influence on Military Architecture
Sforza Castle has undergone multiple reconstructions, particularly during the Napoleonic Wars and the late 19th century.
While da Vinci’s direct involvement in the tunnels remains uncertain, the findings highlight his influence on military architecture.
His sketches, which theorized improvements to the castle’s structure, appear to align closely with the actual underground layout.
Initially, Biolo’s team sought to digitize the area beneath Ghirlanda, an outer defensive wall. However, their scans unexpectedly revealed a hidden tunnel parallel to the castle’s moat, just one meter below the surface.
This passage is thought to have been used by soldiers to defend or reclaim Ghirlanda in case of enemy infiltration.
A Glimpse Into the Past
In addition to these military tunnels, researchers also found a passage believed to have been used by Duke Ludovico Sforza for easier access to the tomb of his wife, Beatrice d'Este, in Santa Maria delle Grazie Basilica.
Although many more underground structures may still be hidden, some may never be uncovered, as Sforza Castle’s original grounds were once six times larger than today.
"These discoveries show that not everything has been lost," Biolo stated. "The underground preserves traces of our past—not just from this era, but many others."
