Grim Batol

From wow.incgamers.com

Was the primary base of the Horde's operations in Khaz Modan during the Second War. Originally a fortress made by the Wildhammer Clan Dwarves, later abandoned and captured by the Orcs. The fortress was originally built to be a mirror of Ironforge, located in the Northern parts of Khaz Modan, called the Wetlands.

Within the depths of Grim Batol was the prison of Alexstrasza, controlled by the Demon Soul, hold by Zuluhed the Whacked. After the Second War, Grim Batol was taken back from the few remaining orcs of the Dragonmaw Clan, and is now under the control of the Red Dragon Flight. Exactly what is going on inside is unknown, and anyone trying to approach the fortress is either chased away or killed by Red Dragonkin guarding the area.