The early 20th century marked the beginning of the Hollywood era, with studios like Paramount Pictures, Universal Studios, and Warner Bros. dominating the film industry. These studios produced iconic movies that captivated audiences worldwide, including classics like Casablanca (1942), The Wizard of Oz (1939), and Gone with the Wind (1939). The Hollywood studio system, which involved a vertically integrated structure where studios controlled every aspect of film production, distribution, and exhibition, enabled these studios to produce high-quality films on a massive scale.