Dark underground cave city. Intricate and abundant lightless archaic and barbaric navy blue architecture, resembling ancient ruins of some sort. Navy blue. Purple mica glistens beneath the surface of the subterranean river. Violet. The cave is illuminated only by bioluminescent plants. Crimson. It's dark and foreboding, but also whimsical and enticing. Deep dark cave, glowing plants, reflective purple river, ancient ruins carved into the navy blue stone walls of the underground. | Anything