The Elemental Plane

One of the four True Planes, the elemental plane is brimming with primal energy. Like the other three True Planes, it partially overlaps with the rest of the planes while also having regions that are "pure," with no overlap.
When not mixed with other planes, the elemental plane is a place of roiling elemental energy: shifting mountains, swirling flames, restless oceans, icy gales, and so forth. Despite its ferocity, the elemental plane has native life, including civilizations, although its people are foreign and alien to the mortals of the Nexus. Most of what's commonly known about the elemental plane is inferred from its impacts on the Nexus rather than being learned straight from the source.