If you want to publicise a cause or gain infamy by vandalising a work of art, then you may as well pick on the most famous of all. When pumpkin soup was hurled at the bullet-proof glass protecting Leonardo da Vinci’s Mona Lisa in the Louvre at the weekend, pictures of the painting obscured by gobs of liquefied food duly appeared across the world. But why is the Mona Lisa so famous anyway? Here are 10 things you need to know about the most idolised painting on Earth.