This photo just shows the inner shell of Brunelleschi's dome in Florence. The roof was actually topped with a copper ball, but the ball was struck by lightening on July 17 1600 and fell from the roof. A man by the name of Andrea del Verrocchio replaced it with a larger ball two years later. Leonardo da Vinci was under his apprenticeship while the ball was being replaced. He was fascinated by Brunelleschi's machines that hoisted the ball onto the roof, so he thoroughly studied them. He made sketches of the machines while studying them; for this reason, many people today wrongly credit da Vinci with the invention of the machines.