Jord: Dawn of a World
The Halls of Stone
Probably the most fortified of cities, however it still manages to fall more than any civilization. The dwarves should probably take a hint.
Below the city, in the Grimdark, lies a powerful fortress named Grimstone, which serves as the only bulwark to prevent the undead infesting the Grimdark near the Halls from eradicating all residents of the city above.