Shelob's lair

Shelob's lair, Torech Ungol, was in the pass of Cirith Ungol. It was a tunnel filled with a foul stench. Its entrance was a cave that led into a tunnel. The walls were smooth, as was the floor, except for an occasional step. It was wide enough for Frodo Baggins and Samwise Gamgee to walk side by side with their outstretched hands touching the side walls. It had various openings off the main tunnel, which then forked. One path led to the Tower of Cirith Ungol, which was blocked by a half-door to keep Shelob out. The other led to an opening blocked by Shelob's webbing. There were multiple exits out of the tunnels, one of which Shelob used to catch up with, and then catch, Frodo Baggins.