A genre is a category that a film fits into, such as horror, thriller, action, western, science fiction, romance, comedy, and war. Western films typically feature cowboys, guns, horses, mountains or deserts, Indians, and stories about taming the frontier. Horror films often contain haunted or dark settings, gloomy atmospheres, isolation, and innocent people in danger. Genre boundaries can be flexible, as some films combine elements of different genres, like Terminator 2 which has elements of both action and science fiction genres.