The next development in movies came in 1927 when sound films or "talkies" appeared. This made movies more popular than ever. Movies began to replace theatre and vaudeville. Moviemakers also started to explore the world of special sound effects. They found out they could express the mood of a scene through the sound of birds singing or through the noise of the wind or rain. The new talkies were more realistic, but they were still only in black-and- white. Then in 1939, "Gone with the Wind", one of the first major movies filmed in colour, was on the screen. The beauty and realism of this film surprised audiences. From this year on, moviemakers learned that colour, too, was very important to set a mood or create a special atmosphere. From the late 1920s until the 1950s, movies were the most popular of all American entertainments. The new film industry, centered around Hollywood, California, gave work to thousands of people. In towns and cities across the country movie palaces anneared For many years movies used to be a