human
Generate for me a description of a dreary scene outside town sewer with lichens and a mound.
assistant
The sewer suddenly empties out into a natural cavern substantially larger than the surrounding tunnels. Phosphorous mosses and lichens, thriving in the damp air, add their light to more of the wall lanterns which, in turn, illuminate a huge mound of rubble growing from the floor of the cavern. Several stories high, enterprising engineers apparently solved the problem of removing the detritus of tunnel excavation by simply dumping it here and forming the mound.