Unreal Reality

I’m working on a piece about my Top 5 ‘secondary realities’ this week. Imaginary cities, invented worlds,  inspired gallactic vistas…from  Tolkien’s Middle Earth to  Asimov’s Foundation Universe, what are the most fascinating unreal realities and why?

I have some idea what my top five are (I’m not giving them away just yet) but I want suggestions for any particularly wonderous worlds of imagination that I might consider, the weirder, cleverer or just plain more escapist the better.

Any and all suggestions gratefully accepted.