All films are considered to be mainstream films. Majority of them are fantasy. The formula of making a successful film is having connections or being a franchise that is trusted by the public. For example Marvel. Everyone expects a good marvel film and they know more will come out of that one films. Franchises creates fandoms and so people can connect over a film. Also having well known film actors involved is a big part. Titanic had Leonardo De Caprio which drew attention to box offices and therefore box offices publicised it everywhere. If a film is publicised everywhere and trailers played around for ADS or Posters being posted more people will get an insight into what the film is about and will be more intrigued into going to watch it. Communication plays a huge part in the formula for a film to become successful as if people enjoy the film they will share it with their friends and so on and the news about this film being good gets spread around and so more people will go to watch the film. Having the film be a well known and popular genre will entice more people to watch the film and help to create a successful film.