Mona Lisa Underdrawing Researchers Discover a Hidden Drawing Behind 'Mona Lisa

No, this isn’t the plot of a Nicolas Cage movie. A special camera went deep into the famous painting
A special camera went deep into the famous painting's nooks and crannies. 

Leonardo da Vinci's Mona Lisa – The Artistic Adventure of Mankind

News The Mona Lisa Blog

Mona Lisa Underdrawing Researchers Discover a Hidden Drawing Behind 'Mona Lisa

Mona Lisa — Discovering da Vinci, monalisa

Mona Lisa': scientists gain insight into da Vinci's techniques

Hidden Drawing Discovered Under 500-Year-Old Leonardo Da Vinci Masterpiece Book Review and Ratings by Kids - Elise Ryan

Louvre and Prado Mona Lisas as stereoscopic image

Real Life DaVinci Code Nearing Conclusion – bloomfield knoble

Mona Lisa, USAM Wiki