Perhaps the most famous smile of all time is the one captured by Leonardo Da Vinci (1452-1519) with his portrait of Lisa Gherardini, wife of a merchant named Francesco del Giocondo, otherwise known as Mona Lisa.

"The most praiseworthy form of painting is the one that most resembles what it imitates," the great master Da Vinci once said.

Who was Mona Lisa? Historians continue to debate her identity, which only adds to her mystique.

Some say she was a young woman from Florence, about 26 years old when Da Vinci painted her on a poplar wood panel. Legend has it that her smile came from the delight she felt at the music which played in the background while Da Vinci painted.

A mere 20 7/8 by 30 inches, the half-length oil portrait was painted between 1503 and 1519.

"Painting," said Da Vinci, "is born of nature."

It is said that Da Vinci loved the painting so much, he always carried it with him. When he died, it was given to the king of France.

Years later, Napoleon Bonapart kept the portrait in his Tuileries bedroom until it was installed in Paris' Musee du Louvre in 1804. The captivating masterpiece lives there today.

In June 2013, Louvre officials unveiled a new lighting system of 34 LED bulbs for the masterpiece to eliminate ultraviolet and infrared energy and bring out the original colors, faded over time.

Mona Lisa is an enigma with an aura of mystery about her. A visual icon, celebrated in song by Elton John and Nat King Cole, her face glows and she is magic! The slight, elegant smile has captured the hearts of millions. She is the most famous, romanticized painting in the history of art.

It is all in the smile...

"Every time you smile at someone," Mother Teresa of Calcutta once said, "it is an action of love, a gift to that person, a beautiful thing."

More DA VINCI Quotations

Your smile is a window to your heart.