[REC] (2007) trivia:
No sets were made for the movie. The film was shot in real locations.
None of the actors knew the fireman was going to fall from the stairs, the reactions of the actors are real.
The DVD wasn't released in the US until after the American remake, Quarantine, was out in theaters and a sequel, [REC]2, was confirmed.
The character of the cameraman, Pablo, is never seen in the film although he can be heard and his shadow is visible.