Crystal City is a floating island crafted entirely from nearly indestructible clear crystal that predates the Great Catastrophe. All of the buildings, streets, docks, and the tall central spire are formed from the very living crystal itself. The city is ruled absolutely by a council of powerful Mages that make their home in the central spire around the Crystal Heart, the artefact that grants them control of the very crystal itself.
The Mages enforce very few laws: They demand first right to purchase any trade good brought into the city, especially magical items; and they prohibit any action that is a direct threat to themselves or the city as a whole. Otherwise, it is up to the citizenry in each of the city’s districts to make and enforce whatever rules they see fit, by whatever means they can afford. This makes Crystal City a paradise for smugglers, pirates, adventurers and political dissidents of all kinds, and it is commonly employed as a neutral setting for negotiations between governments, with appropriate security provided by the Mages at a fair cost.
There have been attempts to take Crystal City on a few occasions since the Cataclysm, but the control that the Mages can exert over the very city itself rapidly showed that such actions are foolhardy at best. They are able to raise defensive walls and towers in moments, turn seemingly save paths for landing infantry into jungles of crystalline razors, and extend fingers of sharp crystal hundreds of yards to skewer approaching vessels, to say nothing of the spells and powers that the Mages themselves command.
The city is roughly circular with the Spire rising hundreds of feet high from the center, and the rest of the city arranged radially around it. There are two sets of docks formed from long, flat crystal spines jutting into the ocean arranged opposite each other, with crystal seawalls to prevent the docked ships from being tossed and damaged when the island is in motion. A great road runs from both docks up to the central courtyard and market around the base of the Spire, and warehouses formed from crystal line the road. The rest of the city is arranged in concentric tiers from the center down to the water’s edge, separated into neighborhoods by roads and walls. Generally the higher tiers have nicer dwellings and the lower tiers have smaller houses or even blocks of apartments. No one owns their home or business, all space is rented from the Mages at a set price depending on size and location, and that money is in turn used to import the fresh food and water that the city needs, as it has no earth for farming or grazing. Those who cannot pay their rent must move to a less expensive unit, or live exposed on the streets until they can afford rent again or passage out of the city.
While the borders and structures of each neighborhood is molded into the crystal itself, each district is allowed to run its affairs as the residents see fit. No order is imposed from outside unless something threatens the whole island. While this does mean that many of the poorer sections are dangerous, dirty hellholes controlled by gangs and Thieves Guilds, some of the poorest neighborhoods have a strong community, with fair leaders and citizen law enforcers and even social support systems. In turn some of the wealthiest neighborhoods become exceptionally dangerous to walk around without personal protection at night, as the wealthy and bored know they can engage in whatever dark ritual or sport they want without fear of reprisal.
A side effect of the crystalline material that makes up every wall and building in the city is that there is very little privacy. It is hard to hang anything because even driving a nail into the wall is next to impossible, and even most glue doesn’t stick to the impossibly smooth crystal. This has led to a very open society, especially since there are no legal repercussions for almost any act, and citizens have simply given up on privacy in most things. On the rare occasion privacy is needed, either entire wooden rooms have to be constructed inside the crystal ones, or tapestries, carpets and decorations have to be adhered to the walls, floor and ceiling with prohibitively expensive adhesives like Alchemical Glue or Sovereign Glue. Among long-time residents, this is generally seen as either amusing or sinister.