D&D Notable Location - Underwater

A location that is known locally or further afield, as a landmark, place of history, magical danger or otherwise noteworthy.
Encounters underwater bring visions of murky seas, vast reefs and dark depths. They might occur in a kelp bed, an underwater cave or by a long-forgotten shipwreck

tools for - dnd5e location quest underwater

terrain:

The Magnificent Lodge of Oblivion is a haunted Asylum. It is at a crossroads. It has a window to another realm. It is cursed ground.
A sunken mushroom ring. It is at a crossroads.
A glittering chasm. It has a store of powerful nature magic. It is blessed by a power of beasts. is where a spirit was bound.
Ruins of Shell Gulf is a stone arch. It is associated with a powerful elemental.
The Catacombs of the Shadowed Pirate is a graveyard. It is in a meadow.
Ruins of Yeowith is a military seaweed garden. It is associated with a mysterious aboleth.
Throne of Three is an unusual chasm. It is associated with vampires. It is disguised by a hallucinatory terrain. has been ripped from another plane.
The Glen of Pirates is a shipwreck. was the site of a renowned tragedy.
A citadel of coral and stone decorated with shells and shiny objects. Aquatic elves often add more decorations and admire their artistry.
The Elemental Mill of Curses is a Palace. It is at a river crossing. It is blessed by a power of the seas.