The wildest frontier in the kingdoms is not reached by moving north or south
or east or west. The most dangerous frontier in Faerun is reached by going
DOWN.
The lands of the kingdoms are riddled with geological uplifts, sinkholes,
caverns, lava tubes, smokeholes and fault lines. Add to this a millennium of
delvings by dwarves and other ancient races, a whole another world lurks
beneath ones feet. This is the world of the Underdark.
The underdark is huge, sprawling, and for the most part unmapped and
undiscovered. It is possible (or so it is said) to walk from the Spine of the
World to Calimshan, without drawing one breath of surface air. Great empires
have risen and fallen deep within the earth without the surface dwellers
having the slightest inkling of their passing.
The underdark areas have several builders contributing to its creation.
Blythe, Tyr, Betandor, Darsian and Eltsac. The underdark is made of several
areas, that are intertwined.
* The Underdark is not to be mapped in any way, shape, or form. We wish to
preserve the mystery, do not spread or claim extensive knowledge of its
geography.