Just because it's controlled by the Sanctuary?
In general, Necropolis looks really cool in the Dungeon – it's all darkness and bright lights... I don't know, I think it's very ominous and impressive.
The Sanctuary also looks good in the Dungeon, but not as much as I'd like.
When I look at the city views in the Dungeon, I always remember how I once wanted there to be a change of time of day, weather, etc. in "Heroes." But, of course, it's not "WarCraft," so you can't divide the game time into day and night...