Altdorf no not that one was/is the capital of The Empire (Warhammer Fantasy) and Reikland. It was known as Kor Vanaeth back when the High Elves colonized the old world. Sitting on the banks of the river Reik and Talabec Altdorf serves as a massive center for trade and is easily the wealthiest and largest city of the entire Empire, possibly even rivaling Marienburg in wealth. It is also olde English for “Old Dwarf”…what? It isn’t? Well, it should be.
The Imperial Tourist industry would describe Altdorf as a beautiful city protected by high white walls that protect a bustling metropolis full of old, stylish architecture. A cultural melting pot, where people from all the provinces of the Empire can meet, mingle and trade. Important landmarks include the Imperial Palace, the Imperial Engineers School and The Colleges of Magic.
In reality. Altdorf is a Feudal World's idea of a Hive City. An absolute stinking shit hole that reeks of filthy peasants, open air sewers, plague, and general death. Buildings are regularly built on top of each-other with no regard for whatever might be below them. The Imperial Palace itself is so absolutely-fuck-huge that absolutely no one knows all the rooms and corridors because every Emperor adds more shit to it like a seven layer cake made of architectural fever dreams and dead laborers. The Colleges of Magic use warding magic from the Grey Wind to hide themselves so they don't get overrun with hobos shitting on everything. The only thing keeping the whole city from catching Nurgle's crotch rot on an epic scale is that they dump everything into the aforementioned rivers. And whatever lowly peasants do die can be easily replaced by a steady train of poor saps making there way in from up river.
In short, it's pretty much a more Imperial and somewhat less savory version of Ankh Morpork.