Instead of sketching Kate Winslet like one of his French girls, Leonardo DiCaprio could’ve been rocking gold chains and questionable dance moves as Dirk Diggler in Boogie Nights. And if you ask him?

The portrait of Mona Lisa by Leonardo da Vinci, more exactly the portrait of one Lisa Gherardini, was executed by fits and starts very early in the 16th century. By now it has been seen by ...