Documentaries aim to document real events using footage, reconstructions, and narration. John Grierson coined the term "documentary" in 1926 to describe films made about real life. Documentaries use facts to make socially critical arguments rather than just presenting facts. There are different types including fully narrated, observational, mixed with interviews and narration, self-reflective acknowledging the camera, and docudramas which recreate events. Features include observation footage, interviews, dramatization, carefully composed shots, and developing an exposition or argument. Gatekeeping involves selecting and rejecting information for the documentary. Narrative structures can be open or closed ended, single or multi-threaded, linear or non-linear, and sometimes circular returning