
Restorers at the Prado Museum in Madrid, working on what they thought was a 16th or 17th century replica of the Mona Lisa, have discovered that the painting was actually done by a student of Leonardo's at the same time as the original.
Museum experts are in the process of stripping away a cover of black over-paint which, when fully removed, will reveal the youthfulness of the subject they say. The final area of over-paint will come off in the next few days.
The original "Mona Lisa" hangs in the Louvre but the sitter looks older than her years as the varnish is cracked. The painting is so fragile that restoration or cleaning is deemed too risky. The Prado version, however, will show the sitter as she was: a young woman in her early 20s.
This is pointillism taken to its limit.

Leonardo da Vinci's 'The Mona Lisa' reduced & remixed down into 140 exact circles of colour. Makes no sense close up. Makes every sense from the other side of the room.
Prints are available.
This is an odd little excerpt from Vanity Fair of a book about the 1911 theft of the Mona Lisa and other art in Paris.
The shocking theft of the Mona Lisa, in August 1911, appeared to have been solved 28 months later, when the painting was recovered. In an excerpt from their new book, the authors suggest that the audacious heist concealed a perfect -- and far more lucrative -- crime.
Expecting new revelations, I read on but it was the same story told in previous books. Regardless, it's a great story and worth the read but nothing new if you've heard it before.
Update: Someone's doing a documentary. (thx, rakesh)
Leonardo da Vinci was a polymath and all that but this would have blown his tiny mind: the Mona Lisa "painted" using just 50 semi-transparent polygons. (via waxy)
In order to explain serial computation vs. parallel computation, the Mythbusters guys pit two paintball guns against each other in a art contest...one shoots one ball at a time and the other very much doesn't. (thx, steve)
Why does the woman depicted in the Mona Lisa appear to be both smiling and not smiling at the same time? The smile part of the Mona Lisa's face was painted by Leonardo in low spatial frequencies. This means that when you look right at her mouth, there's no smile. But if you look at her eyes or elsewhere in the portrait, your peripheral vision picks up the smile. (via collision detection)
A digital rendering of the Mona Lisa from 1964. In the detail view, you can see how it's made up of the digits 0-9, perhaps the world's first piece of ASCII art?