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
Before the 1962–1963 tour, the painting was assessed for insurance at $100 million. The insurance was not bought. Instead, more was spent on security. Adjusted for inflation using the US Consumer Price Index, $100 million in 1962 is around $782 million in 2015 making it, in practice, by far the most valued painting in the world.