A drawing by painter Peter Paul Reubens, allegedly based on da Vinci’s The Battle of Anghiari.

Dave Yoder wants to photograph a Leonardo da Vinci masterpiece. But there’s just one little problem… no one has seen it in 500 years.

The Battle of Anghiari, often referred to as “The Lost Leonardo,” has been missing from the Hall of Five Hundred (Salone dei Cinquecento) in the Palazzo Vecchio in Florence, Italy, for half a millennium. But now Yoder thinks he knows where the world’s most famous unseen painting is hiding, and he wants to build a special camera to see it.

Yoder, on assignment for National Geographic, is trying to raise over a quarter of a million dollars in order to build a camera that is capable of peering through a wall-sized fresco by painter Giorgio Vasari, where many art historians believe da Vinci’s work is waiting.

Da Vinci is thought to have begun work on the painting in 1505 but apparently abandoned it after experiencing problems with the paint. The work then sat in the Hall for over a decade, admired by all who saw it. However, in the mid-16th century the Hall was expanded and da Vinci’s magnificent painting vanished.

Now, Yoder, continuing the work of Florentine art historian Maurizio Seracini who in the 1970s discovered clues to da Vinci’s work hidden in the Vasari fresco, has teamed up with a nuclear physicist to create a gamma ray camera capable of peering through the Hall’s brick wall and photographing da Vinci’s lost painting.

While much of the project is being sponsored by National Geographic, Yoder still has to raise a lot of money to build his super camera. To contribute to the rediscovery of da Vinci’s masterpiece (with a tax-deductible donation), head to KickStarter.