Horror films have evolved over time, beginning with early films from the 1890s-1920s that influenced later American films, through a 'golden age' in the 1930s and the introduction of comedy horrors in the 1940s. Influences like the Cold War led to different gimmicks being used from the 1950s onward, with boundaries being increasingly pushed in terms of graphic violence and sexuality from the 1960s-1970s. Key conventions of the genre include isolated settings, unsettling camerawork and editing, incorporation of sounds to create tension, and visual elements in mise-en-scene like dark clothing and makeup.