To see a UFO or not to see a UFO, that is the question.
This painting is called "The Madonna with Saint Giovannino". It was painted in the 15th century by Domenico Ghirlandaio (1449-1494) and hangs as part of the Loeser collection in the Palazzo Vecchio. Above Mary's right shoulder is a disk shaped object. Below is a blow up of this section and a man and his dog, they can clearly be seen looking up at the object.