Häxan (1922)

Often billed as a horror film, this in actual fact (at least during the one time I saw it) comes across as more of a documentary than a genre piece. Though, one should remember that "documentary" was a slightly nebulous term back then and as such this "history of witchcraft" involves reenactments and full body costumes in order to bring the historical events to life. This, what we would now consider 'unique' approach to the documentary gives it an involving feel, welcoming you into the events it depicts which lends it more a 'horror' theme than would otherwise, typically suit it.