French scientist says he uncovered mystery behind Mona Lisa painting

French scientist Pascal Cotte is making a bold claim about the Mona Lisa. He says he discovered a portrait of another woman lurking beneath the top layer of the world's most famous painting.

Cotte says he made the discovery by shining intense light onto the painting, then measuring the bounced-back reflections to gauge what's underneath.

Not everyone's convinced. Some art historians say the newly uncovered portrait was not a completely different woman, but simply an evolution of the final Mona Lisa.