look closer

The mouth is built from dozens of paint layers so thin the panel shows no brushstroke at all. Its corners dissolve into the shadow of the cheek. Leonardo was still working on this face 16 years after he started it.

In 1503 a Florentine silk dealer named Francesco del Giocondo hired the busiest man in the city to paint his wife. Her name was Lisa Gherardini, she was about 24, and she had lately given the household a son. The commission was ordinary: a wife, a new house, a picture to mark it. The painter was Leonardo da Vinci, who at that point had finished almost nothing, walked away from more work than he completed, and was famous for it. He took the panel, a single plank of poplar 77 centimeters by 53, and started her face. He never gave her back. Francesco paid, presumably, or expected to; the picture stayed with Leonardo. He carried it from Florence to Milan, then over the Alps to France. King François I had given the old man a manor house at Amboise, and the title of first painter, engineer and architect to the king. Leonardo kept opening the box. He worked the face in layers so thin they leave no visible brushstrokes at all. Dozens of near-transparent glazes build the shadow at the corner of her mouth and the softness at her eyes. The technique is called sfumato, from the word for smoke. He was still adjusting her 16 years after he began. He died in France in 1519 with the panel among his things, and the king bought it for the royal collection, which is how a Tuscan housewife ended up in Paris. Giorgio Vasari, writing his lives of the painters decades later and probably never having seen the thing, described eyebrows on her, hair by hair, that the painting does not have. Either he invented them or they have vanished into the varnish; nobody agrees. He also named her, from her husband, La Gioconda, which is why the French still call her La Joconde. For nearly 400 years she hung in royal palaces and then a public museum, admired and unremarkable, one great portrait among many. Then on a Monday in August 1911, a former Louvre handyman named Vincenzo Peruggia walked out with her under his smock. He kept her in a Paris apartment for two years and waited for the noise to die. In 1913 he took a train to Florence to sell her to a dealer, believing he was returning her to Italy where she belonged. The dealer called the police. By the time she came home to the Louvre, her empty frame had been photographed for every newspaper on earth. Crowds came to see the space where she had been, then the painting when it returned. The theft made her the most famous face in the world. She is still there behind glass, half a smile finished by a man who could not stop touching it, watching the room the way she has watched every room for 500 years.