A new online database has gone back to the original Nazi records of their plunder of Europe in an effort to return thousands of works of art to their rightful owners.The database, a joint project between the U.S.-based Claims Conference and the United States Holocaust Memorial Museum, has records of more than 20,000 artworks taken from Jewish owners, museums and libraries across Europe.The Third Reich assigned a special task force to keep a record of seized objects — the Einsatzstab Reichsleiter Rosenberg — as the Germans invaded neighbouring countries.