The subject is most commonly addressed in reference to fictional universes that differ markedly from the real world, such as those that introduce entire fictional cities, countries, or even planets, or those that contradict commonly known facts about the world and its history, or those that feature fantasy or science fiction concepts such as magic or faster than light travel—and especially those in which the deliberate development of the setting is a substantial focus of the work. When a large franchise of related works has two or more somewhat different fictional universes that are each internally consistent but not consistent with each other (such as a distinct plotline and set of characters in a comics version versus a television adaptation), each universe is often referred to as a continuity, though the term "continuity" as a mass noun usually has a broader meaning in fiction.