I snapped off the torch and passed through the tunnel, to come out into a sort of doorway which seemed entirely too symmetrical to have been the work of nature. I was looking into a vast dim cavern, at a somewhat lower level than the outer chamber, and again I shuddered with a strange alien sense of familiarity. A short flight of steps led down from the tunnel to the floor of the cavern--tiny steps, too small for normal human feet, carved into the solid stone. Their edges were greatly worn away, as if by ages of use. I started the descent--my foot slipped suddenly. I instinctively knew what was coming--it was all in part with that strange feeling of familiarity--but I could not catch myself. I fell headlong down the steps and struck the stone floor with a crash that blotted out my senses...