This texture was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
The name says what it does. I tried to create the look of a futuristic sci-fi or fantasy city built below the land's surface.
The controls are simple: Find a variation you like, then choose 5 colors for the city, and 3 for the land. Be realistic, or outrageous... but have fun! :)
city subterranean land underground futuristic sci-fi science-fiction fantasy