During their reign of terror the Nazis stole as much as one fifth of all the major artworks in Europe. Even more were destroyed during World War II. Though the victorious Allied forces returned many pieces to their owners, some remain lost to this day. U sing the recovery of the " Gold Portrait " by Gustav Klimt as an example, filmmakers Richard Berge, Bonni Cohen and Nichole Newnham describe how the looted paintings, sculptures and other works of art were stolen, recovered and sometimes retur ned to their owners. Narrator Joan Allen. Actual Films.