Thieves stole works from Picasso and Mondrian from the National Art Gallery in Athens, Greece, this week.  The heist involved careful planning, as the thieves had tested the alarm system during previous visits to the museum.  Officials could not immediately confirm the price of the paintins, but they were significant works by the two famous artists.  The museum has a variety of international organizations to turn to for help recovering the painting, including Interpol and Europol, which have databases of stolen works.  Stolen art often is used as currency on the black market.  Serbian war criminal Goran Hadzic tried to sell a stolen painting in order to help secure his continued freedom from the authorities.

Citation: Associated Press, Picasso, Mondrian Paintings Stolen in Greece, The Wall Street Journal, January 9, 2012.