Mona Lisa is no ordinary painting, but to realise how extraordinary it is, you need to know how much science Leonardo da Vinci used to create it.

He coated the wooden base with lead and pigment to increase reflectivity and the feeling of depth. He dissected human faces to understand how muscles move the lips, and he also used his knowledge of optics and the retina to mould perception.

No wonder he invested 16 years of his life in perfecting it.