Cities
True cities are fairly rare and impressive things – at once the height of social achievement, and the depth of all too-mortal failures.
Populations are immense, and there tend to be several factions within the city walls, sometimes tolerating each other, sometimes not, but even within these factions the numbers are too great for everyone to know everyone else well, if at all.
Trade with the outside world is commonplace, brisk and profitable, politics are complex if not byzantine, and crime is so well established and organized that the city’s Watch generally cannot prevent it, only mitigate it.