This segment was originally broadcast on Apr. 20, 2008. It was updated on Aug. 14, 2008.
In the art world, there is perhaps no mystery more enduring than the fate of a lost masterpiece by Leonardo da Vinci, the greatest mind of the Renaissance. It was an immense unfinished mural known as "The Battle of Anghiari." For centuries, it has been assumed the work was destroyed, painted over or simply faded away long ago.
Now, after three decades of battling skepticism and bureaucratic resistance, an art detective named Maurizio Seracini believes he's close to solving the Leonardo mystery. As correspondent Morley Safer reported in April, Seracini suspects the mural hasn't been lost at all, but is right where it's always been - for 500 hundred years.
"We are searching for the number one work of art by Leonardo. It was considered the masterpiece of the Renaissance," Seracini tells Safer.
We know roughly what "The Battle of Anghiari" looked like from fragments of Leonardo's sketches and copies made by his admirers before the mural disappeared. It celebrated a victory by Florence over Milan - a furious tangle of men and horses frozen in the fever of war. The painting was in its time, at the beginning of the 16th century, something to behold.
"We have diaries, for example, of people seeing and being in admiration of the horses of Leonardo," Seracini says.
The people came to the Palazzo Vecchio, the town hall of Florence. The city is ground zero of the Italian Renaissance, the rebirth of ideas and the arts in the 15th and 16th centuries that brought Europe out of the Dark Ages. Here, in the shadow of Dante, Machiavelli, and of Leonardo himself, Seracini searches for the "The Battle of Anghiari" using 21st century technology that can peer through paint, through stone walls, even through history.
"You simply have to go beyond what your eyesight can do," Seracini explains.
He believes the mural is on the east wall of the palazzo in the "Hall of 500," which was the seat of government five centuries ago. There, Seracini works on an enormous scaffold. To drop anything could be disastrous: standing right below is a priceless statue by Michelangelo. He is convinced Leonardo's mural lies protected behind an immense painting, which was done by the artist and architect Giorgio Vasari when he remodeled the palazzo in the mid-16th century, 50 years after Leonardo.
Seracini believes the Leonardo mural is on a second wall behind Vasari's painting, separated from it by a small air gap, which appeared on a radar scan. Of the six Vasari murals in the room, only the one has an air pocket behind it.
"Why would you have an air gap just there?" Seracini asks. "Other than you don't want to place a wall directly in contact with Leonardo's mural because you don't want to ruin it, you want to damage it. He left just that air gap enough so that today we can have this masterpiece."