530-Year-Old Sketch by Leonardo da Vinci Reveals Secret Passageways in Sforza Castle
Throughout the late 1400s, Leonardo da Vinci often visited Sforza Castle, nestled in what is now the heart of modern-day Milan, as a member of Duke Ludovico Sforzaโs court. While there, da Vinci not only worked on a painting commissioned by the duke, but produced several sketches depicting the castleโs layout and its intricate passage systems.