Leonardo da Vinci is famous for painting the Mona Lisa. But he was also one of the greatest mapmakers in history. When Leonardo died on May 2, 1519, he left behind maps so accurate that they look like they were taken from an airplane. In Leonardo's time, most maps were rough sketches. They showed towns as little pictures of buildings and rivers as wavy lines. Leonardo wanted something better. He walked across the landscape, measuring distances with tools and noting every hill, stream, and road. Then he drew maps from a bird's-eye view -- as if looking straight down from the sky. His most famous map shows the town of Imola in Italy. He drew every street, building, and open space in correct proportion. It was so precise that modern researchers have compared it to satellite images and found it remarkably close. Leonardo also studied how water moved across the land. He drew maps of river systems showing where water collected, where it flooded, and where it could be redirected. These were not just pretty drawings. Leonardo's maps were practical tools designed to solve real problems, from military planning to flood control.