======Principality and the Desert======

By the time the people of the Underground returned to Principality, they'd seen relatively little of it. It took months of expeditions with CROWN, FLITE, and other aerial robots to build a full picture of the lonely city in the desert.

The first thing they noticed was the desert. Yellow-orange sand almost unbroken for miles in any direction. Whichever way you look, the same sea of sprawling dunes off unto the horizon, broken only by little patches of undergrowth and the occasional sight of the few animals well enough adapted to live here.

One standout mystery that wasn't solved until Nexum was reclaimed was the small flocks of sheep roaming the desert near the city, living off a patch of undergrowth until they'd eaten it almost out of existence and then migrating to the next. It turned out these were Dane's work, part of a project to bring livestock to the desert.

Principality itself is nestled in a little valley between dunes that seems to protect it from the worst of the desert wind, though it's still fully exposed to the heat of the sun. The inhospitability of the environment is betrayed by just how much bigger the industrial complexes above Aqua and Bibere are. The plan, of course, was always to build a thriving, massive city here in the desert, and that simply wouldn't be possible without factories to generate masses of water and power.

Turning back from the desert to the city at its heart, the skyline of Principality is more than distinctive. Every building, every complex, every district was purpose-built by engineers who didn't just believe in science, but in the beauty of science.

Caput sits at the heart of the city, a small park separating the tower where Dane Lawrence once worked from the rest of the skyline. It still stands out today. It's not imposing or authoritarian - not unless you choose to see it that way - it's a functional building surrounded by a public park. In the years after the people came Overground, that park would be as good a place to hold town meetings as anywhere else. The once well-kept gardens tell a story of their own, as the trees and grasses grew wild and then died, being replaced by smaller, hardier desert flowers.

Servus is one of the most notable parts of the city. After all, every robot in service in the Underground today - and those recently gone out of service - had to be built somewhere. It's one massive concentric building that spreads over multiple city blocks, with the most spacious warehouses and workshops you've ever seen. On the top are a smaller number of offices and computerised labs, and on close enough examination a locked, empty server room. Aliz's domain, presumably.

Ludere is different. From afar, it's almost like a void in the skyline. From overhead, you can see its true size; a hundred different arcades, bars, and restaurants. It's most like the Ludere of the Underground, and the most like the communities you're all used to. It's much more neatly laid out, though, following a regular, uniform plan. Some of the places belonged to folks the people of the underground remember. Some of them don't.

Finally, the living arrangements for Principality: above Nidus and Cubile are sizable apartment blocks, dense and built ten or more stories high. You could fit the whole population of the Underground in one of these and have room spare. Still, they must have gone nearly entirely empty - the most lived-in places seem to have been the suburbs over Vicus, Viculus, and - surprisingly - Obscurus, where townhouses are lined up end to end in neat little streets. Hardly sprawling, of course, but the streets laid out even where there are no houses says in no uncertain terms that it was supposed to be, one day.

One thing that every building in Principality has in common is its beauty. It's a functional city, laid out with an engineer's precision and a logistician's eye, but it's more than just that. Almost every sightline down a street is postcard-worthy, and the shots that capture the whole skyline from above are awe-inspiring, especially if you don't know the history of this place. The architects paid no small part of attention to aesthetics, and though it might have gone unseen for a century, their work is, at long last, paying off.