Draenor

From wow.incgamers.com

Draenor before the destruction of the planet.

Also known as "The Red World", Draenor was a boggy swampland and home of the Orcs previous to being cursed by the Burning Legion and sent to invade Azeroth. Orcs then ravaged all other races of Draenor. The Shadow Council then bought order to the land by promising the Orcs escape from the stagnant world of Draenor.

After the Second War, the world was torn asunder by the many portals Ner'zhul opened in his attempt to find other worlds for the Horde to invade. After the destruction of Draenor, it has been called Outland, as it is more a collection of floating fragments in the Twisting Nether rather than a whole world.

Potent power still course through Outland, and is a highly interesting area to control, which has caused the Burning Legion to regain its interest in the once again lush world.