Cellini's Perseus is one of the absolute masterpieces (and that is saying something!) of Florence. Still in place in the loggia (for nearly 500 years!), braving the elements century after century, Perseus never tires of holding Medusa's head aloft. What few people know about this sculpture is that Cellini worked in a self portrait in the back of the helmet of Perseus. The photo below, with the levels raised, shows this pretty clearly:
