Tomb of the Diadem of Dimensions

On his death, Iskar Jarak entrusted the first piece of his regalia, and key to his many victories to a squadron of T'lan Imass to hide and to hold until it was found. They decided to store it and guard it in a buried planar aberration beneath the Graven Citadel in Korel, and there they have waited these long centuries. Instead of having a bottom, the pit opens up to the primordial abyss which exists underneath and around the entirety of the Funhouse.
The 4 planes:

1. Fire
2. Air
3. Death
4. Fae

Purpose / Function

Originally this was simply a sinkhole of planar instability, possibly a portal, or possibly just a tear. The strength of the Graven Citadel above has limited its effect on the surrounding city, and it has since been bent and repurposed as a testing ground and vault to protect the First Crown of Iskar Jarak.

Alterations

The central pit used to be a maelstrom of planar energy, but over centuries of manipulation, Jarak's final guard have repurposed it. Now there are a series of planar layers, each one of which is the layer of another reality. In order to obtain the crown, one must pass through each of them (probably 7 total), as well as face the final guardians at the bottom. If they want, seekers can also seek to bypass the planar gates and seek the maze instead, where they will face the Final Guard themselves, and the booby traps which have resulted from 4 centuries of boredom.

Architecture

The Planar Maelstrom takes the form of an inverted cone which comes to a point deep in the earth. Running all around the sides of it, in the wall bordering the cone lies the maze, which is tunneled through roughly. Some parts seems as if they were carved, others as if they were worn by water. Most of it is balconies, although there are portions where the path burrows fully through the rock, and separates fully from the pit that once held the Maelstrom itself. The full cone is roughly 25 stories deep (250 feet).

Alternative Names

Eye of Planes

Type

Dungeon