Prior to WoW patch 4.0.3, you could easily get underneath Stormwind. Doing this allowed you to travel to the empty lands to the north, and eventually to some mountain ranges south of Dun Morogh, and beyond.
"Walks Through Walls" explores the current state of the land, shattered after the coming of Deathwing. The area underneath Stormwind is gone, and that land to the north is now underwater...
- The Wizard Trokair
