Tuscany — If you manage to elbow your way past the crowds at Paris' Louvre museum to get close enough to stare into the eyes of Leonardo da Vinci's Mona Lisa — and you then manage to break eye contact with the mysteriously poised figure, you might just notice, faraway in the background of the iconic painting, an arched bridge.

The exact location of the bridge, along with much else about the revered work of art by the Italian master, has long been a mystery — until now. At least according to Silvano Vinceti, who's built a career studying the Renaissance masterpiece.

"This is the Mona Lisa bridge," Vinceti told CBS News, pointing at the one remaining arch of an ancient stone bridge in the town of Laterina, in Italy's mountainous region of Tuscany — Da Vinci's birthplace.

The structure dates back at least 2,000 years, to the ancient Roman and Etruscan periods, but thanks to Vinceti's virtual reconstruction efforts, we can imagine what the full structure might have looked like around the time Da Vinci painted the Mona Lisa at the beginning of the 16th century.

"Ancient documents show us how the river looked when Leonardo worked here from 1501 to 1507," Vinceti told CBS News.

His announcement, claiming to have cracked the age-old mystery about the bridge in the painting, has created quite the buzz in the sleepy medieval town of Laterina.

"I think we'll see tourists coming here," predicted resident Laura.

"This town is dying," added Lidia. "Let's hope some rich people come and fix things up around here." 

But the people of Laterina may be wise to hold off on cashing their checks just yet. While what's left of their bridge certainly resembles the one over Mona Lisa's left shoulder, some rival art experts argue the painting really shows another one, the Buriano Bridge, located just a few miles upstream from the lone arch in Laterina.

For years, renowned historians have traced its lineage back to Da Vinci, thanks to evidence that local councilman and professor Renato Viscovo says is irrefutable, and even visible to the naked eye.

"You can see the curvature of the bridge matches the one in the painting," he told CBS News, explaining that the curvature of the arches in the other bridge would have been much steeper and higher than those shown in the Mona Lisa.

The shape and direction of the river at the Buriano Bridge are also identical to the painting, he argues. He brought CBS News to a hilltop that lends a perspective which, Viscovo said, was similar to the one Da Vinci had more than 500 years ago.

"Over there is the town where he painted it," he told CBS News. "He was a guest in the castle."

Today, his view would be obstructed by buildings. As for the other bridge, at Laterina, it simply lacks the evidence, Viscovo said, calling it an attempt to change history to create a tourist attraction.

Some historians have argued that Da Vinci's backdrop wasn't even a real place, but rather a projection of Renaissance ideals — a metaphorical bridge, they might say, between nature and the female form.  

Whatever the case, it's a debate that could almost make the Mona Lisa smile. And while we may never know with 100% certainty what the bridge is in the background, more than 10 million people visit the Louvre every year to see the Mona Lisa, making it the most famous painting in the world.

Perhaps the mystery is what makes the Mona Lisa so irresistible. 

In:
• Mona Lisa
• Italy
• Art
• The Louvre

Chris Livesay

Chris Livesay is a CBS News foreign correspondent based in Rome.

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