The level object. Contains the level's actor list, BSP information, and brush list. Every Level has a World as its Outer and can be used as the PersistentLevel, however, when a Level has been streamed in the OwningWorld represents the World that it is a part of. A Level is a collection of Actors (lights, volumes, mesh instances etc.). Multiple Levels can be loaded and unloaded into the World to create a streaming experience.