This is the inspiration i drew when i was writing the book about the slum planet where factories are dominating the scape. i envisioned this as the before time. Looks sort of like Coruscant from Star Wars. i thought the idea of a City Planet would be brilliant to expand into my original idea for a medieval world.
This is another idea i got from DeviantART. not for the City Planet, but for a different Planet when Alec the main character goes in search for a decent ruler for Isomera. I love the idea of coming up with brand new cultures that have never been seen before. and exploring the universe to see many new places and locations.