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.
Mona Lisa
From December 1962 to March 1963, the French government lent it to the United States to be displayed in New York City and Washington, D.C. It was shipped on the new liner SS "France". In New York an estimated 1.7 million people queued "in order to cast a glance at the Mona Lisa for 20 seconds or so." While exhibited in the Metropolitan Museum of Art, the painting was almost drenched in water because of a faulty sprinkler, but the bullet-proof glass case which encased the painting protected it.