By the early 1940s, every major Hollywood studio was putting the "Technicolor package" to work, and nearly every year set a new record for color footage production. Throughout the decade, filmmakers learned to use color symbolically and expressively, and they experimented with color choices and juxtapositions to explore complex narrative themes. During World War II, Technicolor maintained a strong relationship with the American military, shipping dozens of films overseas to entertain troops. In turn, a number of movies from the era supported the war effort, including This Is the Army (1943) and An American Romance (1944), which relied on Technicolor to boost morale and patriotism. Most popular, however, were the escapist, eye-popping musicals by 20th Century-Fox and M-G-M, including Busby Berkeley’s first film in color, The Gang’s All Here (1943), and the lavish all-star revue film Ziegfeld Follies (1945).