At the end of January on a busy Sunday evening at the Tretyakov Gallery, a man coolly walked up to the painting of the mountain Ai-Petri in Crimea by Arkhip Kuindzhi, appeared to straighten it, then lifted it off the wall and walked away with it. Visitors seem to think he was a museum employee. But a few yards away by a column he popped the painting out of the frame and disappeared through the museum and then out on the street into a waiting Mercedes. The man, Denis Chuprikov, was apprehended the next day and told the police where he'd stashed the $1-million-dollar painting at a construction site. He was tried and sentenced to three years in jail. The painting was returned to the Russian Museum in St. Petersburg, which had loaned it to the Tretyakov Gallery for a retrospective of the painter.