Ivory Tower
The ivory tower may or may not be a true dream-realm, more of a dream structure that appears at times of intellectual need; it is often invoked and populated by academia and intellectuals in search of privacy and isolation. The tower's appearance is mutable and each individual sees it a different way. It may be small or large and has the unique ability to appear in other dream-realms regardless of the desires of the rulers of those realms. It can be unconsciously summoned by those who seek intellectual solitude or consciously summoned by those who have visited it before. While it can be summoned in any dream-realm, it possesses no known exit and escape from it invariably leads to awakening in the mundane world. The interior of the tower is formed entirely of pale stone, bone, wood or in the modern era plastic. The interior is has countless levels, each with its own unique architecture and denizens. The denizens of the ivory tower usually seek isolation, though conversation and commerce do occur fairly regularly; those who engage in any form of physical violence find themselves immediately exiled to the nightmare-lands and find reaching the ivory tower much harder the next time they seek it.