Ankh-Morpork
Ankh-Morpork is the largest city on the Disc with about a million inhabitants. It's also one of the most common recurring locations for the Discworld stories.
The city is located by the river Ankh which resembles more solid ground than water. The city is split by the river in two parts – Ankh and Morpork.
The city is formally ruled by the Patrician but the guilds and the temples are the ones who make the erveryday desicions. The current patrician is Havelock Vetinari. There is very little crime in Ankh-Morpork since much of it is legalised and handled by guilds. It's up to the guilds themselves to keep criminality at a reasonable level.