Adventure Location - Underdark

Short location for an encounter, ambush or distraction. Options for a possible interesting extra.
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 encounters location underdark

terrain: Terrain Type:

A dangerous gorge (it is associated with earth magic)
A stone monument surrounded by shallow water (nearby is a few pale red-fruited tree s)
A large murky pool fed by a spring (it is disguised by a hallucinatory terrain)
A partial collapse surrounded by debris (there is a shifting air current flowing through the area)
A stalactite ready to fall by a limestone rock (a partial collapse could easily happen)
A dried up waterfall (it is touched by death magic)
A pool with a patch of phosphorescent edible mushrooms (there is an inscription here in Undercommon)
A clear river (by an insect-covered mushroom farm)
A shrine to a power of caves near a small beast pen (there is a red and green mosaic of a battle)
A simple covered pit (weird lights appear at random)