What distinguishes a fictional universe from a simple setting is the level of detail and internal consistency. A fictional universe has an established continuity and internal logic that must be adhered to throughout the work and even across separate works. So, for instance, many books may be set in conflicting fictional versions of Victorian London, but all the stories of Sherlock Holmes are set in "the same" Victorian London. However, the various film series based on Sherlock Holmes follow their own separate continuities, thus not taking place in the same fictional universe.