Um'taran

Um'taran is the dread capital of the Dark God, first constructed around a thousand years before the First Wars by the Flesh-Angels and the Accursed.

History
The first defences were destroyed by the Eldar and Men at the end of the First Wars, and reconstructed before the First Calamity. The defences were once again destroyed in the Battle of Um'taran, and reconstructed at some point between then and 4145. During the Host of Man's final advance in 4171, the walls were shattered and the gates obliterated.