Leonardo da Vinci was an Italian Renaissance genius who painted the Mona Lisa and The Last Supper while also filling notebooks with inventive sketches of flying machines, anatomy, and engineering ideas centuries ahead of his time. Left-handed, he famously wrote much of these notebooks backward in mirror-image script, legible only when held up to a mirror. He was endlessly curious about how everything worked, from the human body to the flight of birds, and is remembered as one of history's greatest painters, inventors, and scientific thinkers.