|Sources: The Burning Crusade|
The Expedition Armory is the crumbled ruins of the Alliance Expedition's first base in Hellfire Peninsula. Twenty years ago, shortly after the Second War, humans and orcs fought a terrible battle on Hellfire. In the end, the human lines crumbled, and the Expedition Armory was destroyed by the orcs. Many humans fell, and death knights used their necromantic powers to raise the fallen soldiers into ghosts, known as the Unyielding. They now haunt the ruins of their former outpost.
Possibly the Expedition Armory during the Invasion of Draenor.