The floor grew even softer underfoot as I approached the turn. No more of the red light-globes. The tunnel walls themselves seemed to glow with a putrid yellow light. Phosphorescence of some kind, I wondered, or something even more unpleasant? The air was warm and damp-I could feel my sodden clothes sticking to my skin-and the yeast-like smell was strong, almost choking. I glanced over my shoulder.