Dark underground cave Vegetation. Abundant lightless, archaic and barbaric navy blue architecture with green tinges, resembling ancient ruins of some sort. Dark 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 far below ground, glowing plants, reflective purple river, ancient ruins carved into the navy blue stone walls of the underground. | Anything