D&D Notable Location - Underdark

A location that is known locally or further afield, as a landmark, place of history, magical danger or otherwise noteworthy.
The Underdark is a place of twisting tunnels, constant darkness and strange magic. Encounters might occur in a forest of fungi, amid giant stalactites or by the side of a gaping chasm. It is a place of elemental earth and gates to far realms. Home to fungi creatures, the dark elves and aberrations from the Far Realms.

tools for - dnd5e location quest underdark

terrain:

A noisy waterfall descends into a lake of clear water. On an island covered in glowing green mushrooms is a portal to the surface.
The Vault of Sorcery is a floating cave with large stalagmites. It is in a meadow. It is a dead magic zone (similar to an antimagic field).
A magical river crossing. It is at the edge of a lake. It has a concentration of powerful dangerous magic.
The Forbidden Stairs. A long crystal stairway marked with statues of different underdark races. It is in the area of a forbiddance spell.
A beautiful set of stone steps. It is associated with a magical umber hulk. It is associated with deep rothes.
Asylum of Kilia's Falls is an eerie canyon. It borders a plane of earth. is where a legendary axe was created by a ruthless bard.
An eerie quarry. It is disguised by a hallucinatory terrain. It is associated with a dangerous roper.
A ghostly ruins. It is at the top of a hill. It is used as a temple by a power of luck. It is associated with snakes. is where famous lovers fled.
Ruins of Fighter's Town is a ruins. It is at a crossroads. was the site of a great battle - undead barely defeated a group of city states and a ruler's tomb is build here.
The Isle of Vile Gloom is a mesa. It is at the edge of a lake. It is blessed by a power of magic. It is associated with a plane of air. was for a ritual by a tenacious prophet a few years ago.