Some people think that the Mona Lisa in the Louvre could be a forgery.
Leonardo da Vinci’s painting was stolen in 1911 and wasn’t returned for two years.
There were those who claimed it looked a little different when it got back.
Most experts don’t give much credence to the theory, though, and it has been weakened by X-ray results.
Leonardo painted the Mona Lisa over four years on a piece of wood less than two feet square. Under the surface paint, there are two other portraits of the same woman.
A forger in the early 1900s probably wouldn’t have known about Leonardo’s two failed attempts below the surface or bothered trying to re-create them.