This place shows around forty models of machines reproduced from Leonardo's codices. Some of the exhibits are interactive and copies of the codices are available for further reading. It was supposed to have ended in 2012, but doesn't appear to be in a hurry to leave - and a good thing too, since the church, an attraction in itself (it's the one under which Indiana Jones finds catacombs in The Last Crusade, by the way), was rarely accessible to visitors before.