An Italian art historian claims to have solved a real life Da Vinci Code mystery after identifying a bridge in the background of the artist's famous Mona Lisa painting.

For centuries the enigmatic smile of the Mona Lisa has intrigued experts with numerous theories and suggestions being put forward as to the history of Leonardo da Vinci's masterpiece.

Last month a series of numbers and letters were said to have been found in the eyes of the Mona Lisa, as well as on the bridge in the background, over her left shoulder.