Programme website: http://bbc.in/1m7cUvx For 500 years, the Mona Lisa has remained a mysterious and enigmatic portrait. Now, new research and improved technology are revealing a trail of new clues that could unveil, once and for all, the secrets of the Mona Lisa. Secrets of the Mona Lisa examines new evidence that the painting hanging in the Louvre may not be the original Lisa.