Grand Staircase

A great staircase that criss crosses all of shadow, with many Doors onto those shadows.

Note - this is mostly taken from the Grand Stair as described in Lords of Gossamer and Shadow. The description there is thus:

An infinite network of hidden staircases and linked corridors, linked with magic Doors on either side, linking all of the Gossamer (shadow) worlds. Wardens of the Grand Stair are attuned to it and can activate or deactivate new Doors or manipulate existing ones.