Leonardo da Vinci, born in 1452, had an exploring mind and endless curiosity. He even dissected corpses to learn how bones and muscles work. His paintings are admired today for their freshness and realism. Most popular is Mona Lisa* whose smile has baffled viewers for centuries. His interests extended to botany, anatomy, optics, music, architecture, and engineering. He sketched his ideas for flying machines and undersea boats centuries before the first airplane or submarine was even built.