The Mona Lisa is encased in a 157-by-98 inch box of triplex glass, a gift from the Japanese on the occasion of the painting's 1974 trip to Japan - the last time it left the museum. The subtlety of expression and glow of faces depicted by Leonardo is attributed in part to his practice of painting by the soft light of dusk with a linen sheet drawn overhead to further diffuse the illumination. Although the true identity of the Mona Lisa remains a mystery, most experts believe it is the wife of a 16th-century Florentine businessman, Francesco del Giocondo, who commissioned the portrait (hence the name "La Gioconda"). The painting is also called " La Joconde" (by the French) and "La Gioconda" (by Italians). "Gioconda" also means "a light-hearted woman." in Italian.

The painting has been a part of France's royal collection since the early 16th century. King Francis I purchased the painting from Leonardo after the artist accepted his invitation to live in France in 1517. On December 30, 1956, a young Bolivian named Ugo Ungaza Villegas, stared morosely at the picture for a moment and then threw a rock at it, damaging a speck of pigment near the subjects left elbow. The curators of the Louvre, disturbed by vandalism, put a few of their valuable oil paintings in 1910, the Mona Lisa among them, under glass, and the innovation had provoked a lively guerilla war of protest from habitués of the museum. The new panes were denounced as vulgar shop windows, black mirrors, and in general an affront to Gallic good sense. The Montmartre novelist Roland Dorgelès, one of the leaders of the campaign, descended to the Louvre one morning and indignantly shaved with the aid of his reflection in a Rembrandt self-portrait! The grind of posing may have led to Mona Lisa's rather odd smile. An Italian doctor says he has discovered the secret to Mona Lisa's enigmatic smile a compulsive gnashing of teeth. Filippo Surano believes that the noblewoman in Leonard Da Vinci's portrait suffered from bruxism, an unconscious habit of grinding the teeth during sleep or periods of mental stress. Surano says the strain of posing for the painting could have triggered an attack of teeth grinding. Leonardo performed autopsies on corpses to improve his knowledge of physiology, and ridiculed lesser artists' depictions of human flesh, saying they looked like "sacks of nuts." The bulletproof box that holds the Mona Lisa is kept at a constant 68 degrees Fahrenheit and 55 percent humidity that are maintained by a built-in air conditioner and nine pounds of silica gel. Once a year, the Mona Lisa receives a check-up in which the box surrounding it is opened and the climatic conditions as well as the painting's condition are examined. Following World War I, both the painting and the mystique became fair game and were widely exploited. The Dadaists viewed her as a cultural fetish of the bourgeoisie. Marcel Duchamp painted a mustache and a beard on a reproduction, and called it "L.H.O.O.Q." (a pun on elle a chaud au cul, she has a hot ass.) This site went online on the 19th of April 2001! An Italian man named Vincenzo Perugia tried to sell the work to the Uffizi Gallery in Florence, Italy for 500,000 lire ($100,000). Perugia claimed he stole the work out of patriotism. He didn't think such a work by a famous Italian should be kept in France. What Perugia didn't realize was that while the Mona Lisa was probably painted in Italy, Leonardo took it with him to France and sold it to King Francis I for 4,000 gold coins.

