Documentaries have evolved from early films in the 1920s that captured singular moments, to the development of propaganda films in the 1930s like Leni Riefenstahl's "Triumph of the Will." Direct cinema in the late 1950s and cinema verite in the 1960s strived for a naturalistic style. John Grierson in the 1920s believed documentaries could build morale. While Robert Flaherty's 1922 film "Nanook of the North" was pioneering, it was criticized for staging some scenes. Audiences have become dependent on media like documentaries which they view as truthful sources of information.