Traditional cities, consisting of suburban sprawl with a small urban core, surrounded by large farms, did not survive the zombie plague. Their lack of centralized resources meant it was harder to ensure everyone had access to uncontaminated water, and because of their lack of fortifications, most were unable to keep the zombie plague outside the city.
Instead heavily fortified walled cities became the norm: notable examples of this are the Monastery of Ludzska and Dom Lied. This allowed stockpiling of food and uncontaminated water, as well as a safe place for the people to stay when a zombie column was passing through. Along with the fortified city, there was also typically a large area that was walled off by a smaller secondary wall that was used for farming.
Monastery of Ludzska
Sitting at the base of Mt. Ludzska, the Monastery of Ludzska has been a place of religious worship for Ludzians for over 3000 years. Originally a small temple, it was dismantled and abandoned in Y-2700 as the Shtot Imperium declined. Around Y-1200, as Prosanites were headed north, Ludzians returned to the site and constructed the Monastery of Ludzska that survived the Z-plague.
It consisted of two walled areas: the Shrine, which was surrounded by a heavy wooden wall, and the Gardens, which were surrounded by a low, mostly decorative wall. The Shrine backed onto the base of the mountain, where a small staircase ascended most of the mountain to arrive at the Observatory.
When news of the incoming Z-plague began to arrive, religious refugees descended upon the Monastery. To support them, sections of the Gardens were planted with fast growing trees, and large barracks were constructed inside the Shrine. When the first Zombie arrived in Y-195, it was disposed of in a large stone bonfire outside the walls.
As more refugees arrived, the city spread up the mountain, precariously perching small wooden structures on the mountain face alongside the stairs. Engineers began constructing tunnels in the base of the mountain to provide additional housing.
Ultimately the monks found the model unsustainable, and devised the Modern City Model.
First, three smaller fortified barracks were created outside the main walls around the deeper wells. Each of these had a priest in charge, and were capable of being locked down and incinerated in case of a breach. Long bamboo bridges could be used to connect these barracks to the Shrine, and were easily discarded in case of attack. Inside each of the barracks they had a reservoir of food and water to survive a month, and the Shrine contained an additional year of food and water stockpiled in granaries.
The shanties on the side of the mountain were removed, and the tunnels dug into the mountain became temples again. Ultimately four of the smaller fortified barracks were constructed: only one was ever breached by a zombie attack.
Dom Lied was a citadel in the center of the Ahnennia region, and up until the zombie plague was a military command post. When the Z-plague approached from the Ahnennian Highlands, Dom Lied was one of the few places not impacted by superstition, in part because of the charisma of its commanding officers. Protected by thick and high stone walls, Dom Lied provided an impenetrable fortress.
However, it didn't have the low outer wall or the difficult terrain of the Monastery of Ludzska. It was beseiged by three columns, each of which starved nearly three quarters of the population. These seiges were lifted as the columns were distracted and moved off towards the bigger targets of Dom Kurz and Dom Karstan, both of which ultimately did not survive the Z-plague.
The city of Dom Lied was ultimately built directly on the walls. Most of the buildings reached seven or eight stories, which gave them an impressive view of the outside world. While individually the buildings weren't very structurally sound, they leaned on each other to provide their stability. In the center the original keep still stood, dwarfed by the ramshackle towers surrounding it; it allowed the military leaders to maintain a semblance of order in the early years.
After a fire that decimated nearly half the city, the commanders decided to take a different approach. A low wall was constructed along the edge of the farmlands to allow them to begin recovering the food and supplies they had lost. Inside this wall they constructed several fortified bases, each with their own stockpile and supplied with water from the central fortress. These fortified bases contained large stockpile rooms that were fireproof, sewers, and resevoirs. Wooden towers were built on top of them for living quarters, shops, and the city as a whole. Heavy wooden bridges connected these fortified bases to each other, and heavy wooden gates closed off the region in-between the bases. The citadel was connected to the bases by large wooden stairs.
Slowly, the Citadel returned to being a military fortification, before ultimately being torn down and rebuilt into the modern meeting hall in Y95.