Documentaries are non-fiction films that are commonly an hour long and shown on TV. They were defined in 1936 as the "creative treatment of actuality." There are several key features of documentaries including observation, interviews, dramatization, mise-en-scène, exposition, and establishing a line of argument. There are six main types of documentaries: fully narrated, fly on the wall, mixed, self-reflective, docu-drama, and docu-soap. Fully narrated documentaries include an off-screen narrator, fly on the wall relies solely on observation, mixed uses interviews and narration, and self-reflective has the director speak directly to the camera