World's Edge Mountains
The World’s Edge Mountains are the greatest range of mountains in the known world, stretching from the northern Old World to the Southlands, and forming a natural and insurmountable barrier between the Old World and the Dark Lands. Its tallest peaks tower almost 15 kilometers above the plains below. The great height of the mountains makes the range impassable except through mountain passes. The whole mountain range is undercut by ancient underground passageways built by the Dwarves, which allow passage beneath the mountains.
In the distant past the mountain range was the heart of the Dwarf empire. During this time numerous fortress cities known as the Dwarfholds were built into the rock in the mountains.