In eons past the cosmic stasis was shattered. The planes of law and order, chaos and change were destroyed; sending the Material world and its neighbors into disarray. They finally settled into a new configuration of overlapping boundaries.
The Material
The Material is the plane in which all other planes merge. This mixing of elements creates a great diversity. The Material is the most well documented of all the planes due to its stability. It is unknown if the plane is finite, bound on all sides by the borders with the elemental planes, or if it exists in infinite pockets of thoroughly mixed planar forces.
The Planes
Outside of the Material is everything else. There are six primary planes that merge and meld, each creating overlapping but distinct regions. This is often visualized with an octahedron with a point in the center connecting to the vertices. Each vertex represents one of the elemental planes. The edges represent the planes connecting them, and the lines connecting to the center representing the near-material planes.
An alternative model exists to represent the planes. Perhaps another angle when metaphorically looking from above. This model splits the planes into two groupings: Stage and Actors. The Stage is shell that has hemispheres representing Sky and Earth meeting with a ribbon surrounding them representing Water. The Actors are Life, Death, and Fire. This is represented by two curved cones (Life and Death) touching vertices at a point wrapped in a flared ribbon representing Fire. The two shapes are overlaid and at the very center is the Material. While this model doesn't account for direction as well as the octahedral, it does capture the different shapes of the planes, with the Stage planes seeming far more distant (in that the near Material areas of these planes are not as reflective of the Material) and the Actor planes taking on an unbearable and complete fullness of their elements.
The Heavens: Planes of Life
Celestia, Celestial Heavens, Anima Mund
Usually presented as being above the other planes, the planes of life are from which souls and animating energy flows. The Wellspring is the prime plane of life, and strangely enough is hostile to all life. The pure intense positive energy overwhelms and consumes nearly all creatures that would enter it. But sitting on the edge of this and all other planes within the Heavens is Heliopolis, through which all souls flow downward into the Material. The other elements mix with life to create the Forge (fire), Nebula (sky), the Reef (water), and the Hyphae (earth). Near the Material, the plane of life is known as the Umbra, a brilliant night full of spirits.
The Inferno: Planes of Fire
Igneous
The prime plane of fire is a white hot sea of raging flames. Most creatures are not accustom to the heat, and so it is not well explored. At the edge though sits the City of Brass, a massive metropolis of artisans. Above it floats a ball of fire which feeds the heat of Mt. Cain. Below it an ever flowing river of molten iron. The planes of fire that border the other elements are the Forge (life), Arkas (sky), the Pyroducts (earth), and Crematoria (death). Where it borders the Material it's known (deceptively) as the Black Desert.
Endless Expanse: Planes of Sky
While the octahedral model of the cosmos puts the planes of life above everything, the plane of sky literally sits above the material. One travels upwards to the sky into the Jetstream where they are whisked away to domains of air and wind. It's debated which city is the nexus of the planes of sky, but once one has traveled through the Jetstream they will find themselves in either Leng or Kadath, the city of dreams or nightmares. From here one can travel deeper into the plane of sky, the Tapestry proper, or they can divert to the elemental half-planes of Nebula (life), Arkas (fire), the Typhon (water), or the Void (death).
The World Sea: Planes of Water
Another Stage plane, the Endless Glass is reached by sailing beyond sight of the shore (or occasionally through whirlpools). A sailor drifting on these waves long enough will happen across the nexus of Atlantis. This floating city is the meeting point of the Endless Glass (near Material) and Crushing Depths (prime elemental) planes. It also has rivers flowing out to the other elemental planes: the Reef (life), Typhon (sky), the Quagmire (earth), and the Derelict Seas (death).
The Vaults: Planes of Earth
A particular danger to travelers of the Yormir and the Fell, the planes of earth are physically located underground. When one travels through tunnels hewn by mortal or monster, they can cross over into the Barrows as they approach the planes of earth. Traveling deep enough a spelunker will happen across the nexus of Agartha. Tunnels wind every which way from Agartha. The noble houses guard the passages that lead deeper into the prime elemental plane known as the Crystal Vaults. Of course, other tunnels lead to other elemental planes: the Hyphae (life), Pyroducts (fire), the Quagmire (water), and the Catacombs (death).
The Underworld: Planes of Death
Cthonia, Cthonic Vaults, Land of the Dead
Finally, below all the rest, lies the Underworld. The muted lands of the dead are where all mortals must one day travel. Near the Material is a dark reflection known as the Shadowlands. The other elemental planes of death can be navigated from here and include Crematoria (fire), the Void (sky), the Derelict Seas (water), and the Catacombs (earth). All roads slowly descend to the First City: Ur. This ancient city made of monolithic stone sits atop a vast empty nothing; the true end; utter annihilation: Oblivion. Anything that falls here quickly succumbs to entropy and destruction. Terrifying monsters lurk within and rip flesh and soul apart, turning it to ash or dust or diffuse dead energy.
