Small oil portrait by Leonardo da Vinci, begun around 1503 in Florence, showing a woman — most likely Lisa del Giocondo — before a hazy landscape with an ambiguous smile. Built in Leonardo's sfumato technique of gradated tone without hard edges, it was always admired. Its transformation into the world's most famous painting came largely from an accident: its theft from the Louvre in 1911 made it a global media sensation, and mass reproduction did the rest. It now hangs behind glass in the Louvre, the most visited and most reproduced artwork in history.
On August 21, 1911, a workman walked out of the Louvre with the most famous painting in the world hidden under his smock. Except it was not yet the most famous painting in the world. It was a well-regarded Renaissance portrait by Leonardo da Vinci, admired by experts but not mobbed by crowds. The theft changed that. For two years the empty wall drew more visitors than the painting ever had, the world's newspapers ran the hunt on their front pages, and when the Mona Lisa came home she was a celebrity. The crime did not make her a great painting. She already was one. It made her the most recognized face on earth.