Another story about recovered artworks whose owners were never found. Israel's national museum is hosting two new painting exhibits with a tragic history.The paintings featured at the exhibits were stolen by the Nazis during World War II and were never reclaimed by their rightful owners. Many were killed in the war.The exhibits include paintings by masters like Henri Matisse, Claude Monet and Georges Seurat.Visitors who recognize a painting as their own and can prove it can file a claim and potentially take it home.The first exhibition called "Looking for Owners," is made up of 53 paintings on loan from French museums.The companion exhibit, "Orphaned Art," includes mostly lesser-known paintings and items given to the Israel Museum decades ago by a group known as the Jewish Restitution Successor Organization, which was entrusted to return unclaimed Jewish property in postwar Europe.James Snyder, director of Israel museumm, said, "Our feeling about them is that our job is to hold them in custody in a way as a kind of memorial to their loss and when the opportunity arises to return a work, we are happy to do so."The institution has also launched an Internet database of all the looted art in its storerooms.The Israel Museum says that over the years it has returned some 20 pieces to owners or heirs.Experts say anywhere between 250,000 to 600,000 pieces of art looted by the Nazis were never claimed and are in the possession of museums, governments and private collectors.