Mosquito drain

Mosquito drain starts off with a 2400 x 1800 RCB then connects to a smaller size guessing 2000mm RCP sanitary drain this was a least a good couple km as it continues down more but the more you go the nastiest it gets so there for couldn't walk it to the end the reason why i call it the Mosquito drain well obviously because of the Mosquito's that are there like in the 1000s lots of strange noises in this drain seen some occult like symbol but moments before seeing the symbol felt like someone was standing behind me and also when i was leaving felt like i was being watched so i looked up some symbols involving drains/tunnels/construction anything that has to do with underground couldn't find anything that came close to this also as i ventured down more seen another part that's been spray painted over dunno if that was another symbol all in all interesting explore