Deepholm was (also called Deepholme or Deephome, though the latter may be a misspelling or typo) is a continent situated far below the Skywall.
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Temple of Earth.

The surface is rough, covered with fissures and craters, and it regularly quivers with earthquakes. When the realm of fire beneath breaks through, massive volcanoes form, until Therazane's earth elementals can put a halt to the incursion.
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Therazane's Throne.

Deepholm is lined with caves, tunnels and endless passageways. Worms, burrowing animals and other subterranean creatures abound. Gems and jewels of all kinds, including those not known to Azeroth, can be found within, though they are considered the property of Therazane herself. No mining efforts are permitted in her realm. Some sages believe that a few of the precious stones possess strong innate magical powers, but the truth of this speculation may never be verified.

The surface of this land is not pleasant to live on, but hardy plants and animals do eke out an existence here. Life for them is short and vicious, but Therazane the Stonemother nurtures them when she can. Striking at those she considers her "children" is the quickest way to earn her enmity.

In a few rare places, the surface of Deepholm resembles a rocky, deserted section of Azeroth. Visitors to the Elemantal Plane can find some measure of rest here, although the ground does shake and tremble with frightening regularity. Underground, travelers face not only quakes, but also cave-ins, rockslides and other dangers.

One of the four "levels" of the Elemental Plane, occupied by the Earth elemantals.