There's only 4 planes of Azeroth. They're: Air, Earth, Fire, and Water.
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Description
When the titans defeated the Old Gods and
brought order to the world, one of their first acts was
to banish the Elemental Lords and their servants to
a prison within the Twisting Nether. These agents
of chaos could not be allowed to roam freely, or they
would disrupt the new order the titans sought to
create. Thus, the titans fashioned a separate plane
to hold their old foes. Over the course of a short
period, they cast all the elementals they could find
into this hastily crafted “jail.”
The plane the titans created is spherical and
comparatively small — about the size of a single
world. A glowing yellow orb, casting forth light and
heat, hovers near the top point of the globe, acting
as the “sun” for the entire plane. Normal levels of
gravity pull physical objects toward the bottom of
the sphere, where the realm of fire lies. A thick
layer of permanent, tunnel-ridden stone supports
the earth and water on the surface. Above, a layer
of air hangs over the ground, never reaching the
fiery turbulence beneath.
The sphere itself is curved in a curious way that
tends to baffle creatures of Azeroth’s reality. As
befits the plane’s prison function, escaping through
ordinary movement is impossible. A creature attempting
to move out of the sphere simply curves
inexorably around, moving toward the other side.
Thus, if one were to sail across the ocean in a boat,
he would eventually arrive on the exact opposite
side of the plane’s sole continent. The land itself is
slightly larger than Kalimdor, while the seas are
about the same width in all directions.
The four elements that make up the plane are
constantly in opposition and tend to shift and tear
at each other, sometimes violently. Volcanoes rip
through the solid mantle, assaulting both the land
and sea realms wherever they can. The air swirls in
unpredictable storms, producing whirlwinds and
hurricanes that rake the surface. Yet through all
this, life exists, filling the skies and lands with
creatures similar to those on Azeroth, as well as
those as yet unknown to sages.
Access
Reaching the Elemental Plane can be accomplished
through any standard method (i.e., those
spells that allow planar travel, such as plane shift or
gate). Elementals can also be summoned using the
appropriate spells, but these spells do not permit
travel in the opposite direction.
Some areas on Azeroth provide direct access to
specific locations upon the Elemental Plane. Scholars
refer to these areas as “transit nodes.” Although
no permanent gate exists, opening the transit node
can be accomplished through a simple dimension
door spell cast within 30 feet of the node. The
dimension door allows the traveler to step through
directly into the Elemental Plane at a specific spot
corresponding to that transit node. In other words,
a traveler can later use the same node again to reach
the identical location — a far more reliable method
of travel than plane shift, for example.
Transit nodes exist only in specific elementalbased
locations on Azeroth, such as within
volcanoes, underneath deep oceans or lakes, and
the like. Identifying one while traveling in the
appropriate terrain requires a DC 35 Knowledge
(the planes) or Spellcraft check.