Ultima Ratio Regum v0.6.0 Adds Cities, Fortresses, Coins
To be looked at and not touched.
Dwarf Fortress's development is a joy to follow along with, but its age means that each new update, however large, is designed to add greater complexity and nuance to its simulation, and much of the heavy lifting for its procedural world generation was done long ago.
Ultima Ratio Regum aims to be a roguelike crossed with a 4X, and at this stage it's not as far advanced as Dwarf Fortress nor even really a game. But that means you get to follow along as the fundamental code underpinning its world is formed. Version 0.6.0 was just released and it takes the overworld map added long ago and drills deeper, so that each city that appears upon it can now be walked around at street level. Or as the patch notes put it, you can now "Explore massive and varied feudal cities (each able to support a population of ~300,000+), each with its own range of districts, architectural styles, and buildings influenced by the political and religious choices of its civilization."
There's more to do than just walk, at least. Each new area in the game can also be looked at and read about via the in-game encyclopedia. If you choose to look at something, the image you'll see will be similarly created via procedural generation. URR uses ANSI art - like ASCII but with a larger set of characters - and is strangely beautiful. Previous builds included procedural riddles and procedural vines and procedural keys and procedural wheat. I think there's coins now.
The next update should come in March with 0.7's addition of building interiors, before "core gameplay" begins to be added in 0.8 with the simulation of NPCs. Until then, I highly recommend downloading the latest build (it's free) and treating it as a kind of fantasy world walking simulator.