Art experts have made a surprising discovery of the world's most famous paintings, the Mona Lisa. They claim to have found a set of tiny letters painted into the eyes and a number under the bridge in the backdrop of the painting. Tom Fearon looks into the cryptic message in the 500-year-old portrait.

For centuries, Mona Lisa's eyes have enchanted art lovers admiring Leonardo da Vinci's celebrated masterpiece. However, few people dared imagine the eyes contained an actual code.

Stefania Romano from Italy's National Committee for the Valorization of Cultural Heritage says the latest discovery leaves more questions than answers.

Stefania Romano said, "We believe that in the eyes of the Mona Lisa there are two letters: an L in her right eye, and an S in her left eye. It is also possible to notice the number 72 with a simple magnifying lens."