The Mona Lisa’s secret

From The Guardian: "What is the Mona Lisa's secret? She smiles so enigmatically under the all-but-invisible transparent silk veil that covers her hair, turning her brown eyes as if she has just seen someone come into her field of vision. The fascination and fame of this portrait, begun by Leonardo da Vinci in 1503, has always related to the elusive personality it communicates. Giorgio Vasari in the 16th century claimed Leonardo employed musicians and jesters to make Lisa smile. Walter Pater in the Victorian age thought she resembled a 'vampire.' Modern viewers sometimes see her face as androgynous, an observation first made by Marcel Duchamp."