'What does the world look like from the moon?' 'How do our bodies work?' 'Is it possible for people to fly?' 'Can a make a horse of bronze that is 8 meters tall?' 'How can we have cleaner cities?' All his life, Leonardo da Vinci asked questions. We know him as a great artist, but he was also one of the great thinkers of all time, and even today, doctors and scientists are still learning from his ideas. Meet the man who made a robot lion, wrote backwards and tried to win a war by moving a river...