A European collector has bought a 17th century copy of Leonardo da Vinci's Mona Lisa painting for 2.9 million euros ($3.4 million), a record for a Mona Lisa reproduction, in an auction at Christie's in Paris on Friday. Known as the "Hekking Mona Lisa," after its owner who unsuccessfully argued that a copy he had bought in the 1950s was the real thing, is one of many reproductions of the original, which hangs in the Paris Louvre museum. "This is madness, this is an absolute record for a Mona Lisa reproduction," a Christie's spokeswoman said. She said there had been...