A charcoal drawing housed in another art collection for more than 150 years may have been a sketch for the Mona Lisa, a French art expert says.
The charcoal portrait of a nude woman, known as the Monna Vanna, was previously attributed only to Leonardo da Vinci's studio.
But experts have found enough clues to suggest the artist worked on both.
After tests at the Louvre Museum in Paris, curators believe the sketch is "at least in part" by Leonardo.
To read more:
http://www.bbc.co.uk/news/world-europe-41436057
You may also like to read:
* Da Vinci Discovery: Rare Drawing, Valued at $16m, found
* Paris Museums Now Open 7 Days a Week
