Mona Lisa
The painting is thought to be a portrait of Lisa Gherardini, the wife of Francesco del Giocondo, and is in oil on a white Lombardy poplar panel. It had been believed to have been painted between 1503 and 1506; however, Leonardo may have continued working on it as late as 1517. Recent academic work suggests that it would not have been started before 1513. It was acquired by King Francis I of France and is now the property of the French Republic, on permanent display at the Louvre Museum in Paris since 1797.
Mona Lisa
In December 2015, it was reported that French scientist Pascal Cotte had found a hidden portrait underneath the surface of the painting using reflective light technology. The portrait is an underlying image of a model looking off to the side. Having been given access to the painting by Louvre in 2004, Cotte spent ten years using layer amplification methods to study the painting. According to Cotte, the underlying image is Leonardo's original Mona Lisa.