Hall of Infinite Doors

The hallway gets rough as you continue on, losing its shape and growing damp and cold. The walls and the floor merge, and the footing is treacherous. The hallway looks for all purposes like an underground cave. The hallway is lit by a phosphorescent lichen that clings to the walls, and the "doors" are merely rough openings in the cavern wall, each with a curious mat set before it.