Isleworth Mona Lisa
According to Leonardo's early biographer Giorgio Vasari, Leonardo had started to paint "Mona Lisa" in 1503, but "left it unfinished". However, a fully finished painting of a "certain Florentine lady" surfaced again in 1517, shortly before Leonardo's death and in his private possession. The latter painting almost certainly is the one that now hangs in the Louvre. Based on this contradiction, supporters of the authenticity of the "Isleworth Mona Lisa" claim it is the unfinished "Mona Lisa", made at least partially by Leonardo, and the Louvre "Mona Lisa" a later version of it, made by Leonardo for his own use.
Lego in popular culture
A 2011 exhibition titled "Da Vinci, The Genius" at the Frazier History Museum in Louisville, Kentucky attracted attention by having a "Brick Art" Mona Lisa replica constructed by Lego artist Brian Korte. 
Lego builders such as Eric Harshbarger have made multiple replicas of Mona Lisa. 
Matching the approximate 21 by 30 inch size (535 x 760+ mm) of Leonardo's original requires upwards of 5,000 standard Lego "bricks", but replicas measuring 6 by 8 feet have been built, requiring more than 30,000 bricks. 
The Little Artists (John Cake and Darren Neave) have created an entire Modern Art collection in Lego form. Their exhibition 'Art Craziest Nation'
was shown at the Walker Art Gallery in Liverpool, UK.