AP Photo

Few paintings have been more viewed, more analyzed, studied and interpreted, than Leonardo da Vinci's "Mona Lisa," otherwise known as "La Gioconda."

Despite this, no one has come up with an explanation for that enigmatic smile, or a lot of other details in this painting that, despite all the ink and hot air expended on it, measures a mere 77 by 52 centimeters (about 30 by 21 inches).