6015396 Imperator, ocean liner built for the German Hamburg America Line in 1913, used by the Allies to transport American troops back to the United States after the end of the First World War (b/w photo) by German Photographer (20th Century); Private Collection; (add.info.: Imperator, ocean liner built for the German Hamburg America Line in 1913, used by the Allies to transport American troops back to the United States after the end of the First World War. Illustration from Our Times Illustrated, 5 April 1919.); 穢 Look and Learn.