The stairwell is Immense, 40 yards across with a ceiling carved so high it is lost to the sight of most creatures who walk it. It completes a turn every 200 yards.
It is constructed of a smooth brown stone. This brown stone still forms the core of the stairwell, but it has long since been covered over by the bones and debris from thousands and thousands of slain travelers and denizens.
It is on this layer that travelers tread now and only the most ancient or wise denizens know that those early stone steps exist.
Atop the hardened bone surface is a loose layer of bones, the odd corpse, chunks of rotted and useless equipment and bits of rusted iron.
The top layer is in the shape of a stair but its loose construction make footing treacherous and slow.
The walls are covered with horrible carvings depicting the worship of evil Gods by creatures of all sorts, but mainly Devils. The outlines of these carvings glow with a different color every 24 hours providing light and a method of keeping time.
There is a near constant smell of rotting meat and the constant grinding sound of bones rubbing together. The strange glow from the wall carvings creates weird shadows, and those carvings always seem to squirm when viewed out of the corner of the eye. Even stranger, they sometimes feel like they are moving when a tired creature leans against them .