Who built the colossal derricks and hoists and all the abandoned superstructure that extend down, down below the surface of Ain 4, deep down for mile after mile? Were they building something that extended down to the core of the world, or were they trying to reach the surface? How many levels are there in all these dark, dismal and heavily polluted areas? Where are the builders? What happened to them? Who--what--lives down there now?
