Blub is an Italian street artist whose real name is as much a mystery as Banksy's. He has added snorkel masks to a string of classics, including the Girl with a Pearl Earring, da Vinci's Mona Lisa and Piero della Francesca's Duke and Duchess of Urbino (the 15th century original of which graces the city's hallowed Uffizi Gallery). His works are displayed at Cappelleschi Gallery in Belgium.