In 1507, when Leonardo da Vinci painted a portrait of Mona Lisa Gherardini for her husband, a merchant named Francesco del Giocondo, the husband did not like the finished painting and refused to pay for it.
Was it because of her mysterious smile which still puzzles viewers today? No one knows. But King Francis I of France, who was greatly interested in art and spent lavishly on collecting paintings, bought it ten years later to hang in his palace bathroom. He paid 4,000 gold florins for it, or about $69,000.
The Mona Lisa, now hanging in the Louvre Museum in Paris, is valued today at $100,000,000!