A documentary is a essentially a non-fictional film that tells a story about real-life events, presenting factual information about the world outside the film, intending to document reality to maintain a historical record.

Examples:

• O.J: Made in America (2016, Ezra Edelman)

• David Attenborough: A life on Our Planet (2020, Jonathan Hughes, Keith Scholey, Alastair Fothergill)

• Night and Fog (1955, Alain Resnais)

The difference between a documentary film and a documentary series is that while a documentary film seeks to tell a single story within a compact timeframe, a documentary series must break its story into multiple chapters that are each capable of standing on their own, or it has a main theme such as crime and has a different story each episode.