Documentary movies are an effort to showcase some sort of reality. Great care is being taken in choosing the scenes in such types of movies. Generally no actors or scripts are involved in such kind of movies .These movies rely on voice over recitation or narration which describes the scenes of the movie. It also includes interviews of people and their viewpoints.
These are low budget films without and they lack the backup of any large production house. Where documentary movies used to be comparatively difficult to understand as a genre, contemporary documentarians like Michael Moore and have extended the general position of such type of movies.
The initial movies that came up were basically documentary movies and they featured only one shot of events. Later on these movies had some agenda on which they were based for instance Triumph of the Will, depicted the great heroics of Adolph Hitler. There were documentary movies that communicated their agenda itself without any narration as well.