Ankh-Morpork is a major City-State of the Disc. It is roughly equivilant to a mix of Roundworld Tallinn, Prague, 18th Century London, 19th Century Seattle and Modern day New York.
Ankh-Morpork lies, or more accurately squats, on the Sto Plains. It is bisected by the River Ankh into its original two cities, snooty Ankh and squalid Morpork, although truth be told the entire city is rather squalid, not to mention dirty, pestilent, and with a smell that has an almost physical punch. With multiple roads running away from Ankh-Morpork as well as the traders of the River Ankh, Ankh-Morpork is the trading capital of the Discworld.
Ankh-Morpork was once an absolute monarchy but now rules by a semi-democratic process, with the Patrician - currently Lord Havelock Vetinari - holding the most power. It is semi-democratic because the system is one man, one vote: Lord Vetinari is that man, and he has the vote.
In theory most major guilds and remaining nobleman have a large say in what should happen in the city's day-to-day affairs, but Lord Vetinari has a hold over the city by being absolutely indespensible to it, although he does let some organisations (see Ankh-Morpork Council) get on with all the laws and things.
Ankh-Morpork is very much a city of guilds. Almost all guilds have representatives here, as do the actual guilds of Ankh-Morpork. In fact the headquarters of many of the guilds lie in Ankh-Morpork, among them:
The Ankh-Morpork Guild of Assassins is located on Filigree Street, Morpork.
The temples of Hat, Sek, Guffnork, Sandlephon and Gapp are located on the Street of Small Gods, Morpork. Fish's Temple is located on Cockbill Street, Morpork; Pishe's Gardens are in the Apocothary Gardens in Ankh.
The main Guildhouse for the Ankh-Morpork Guild of Thieves, Burglars and Allied Trades is located on the Street of Alchemists, Morpork.
The two local warrior guilds are the Ankh-Morpork Palace Guard, located in the Patrician's Palace in Morpork, and the Weapon Masters' Court, on Vagabond Street, Morpork.
The local witch for the entire city of Ankh-Morpork is Gennie Applebottom, in Holoferns, Morpork; while one cannot become a witch there, you can obtain transport to Granny Weatherwax instead.
Apart from offering representatives of every guild (or, more accurately, professions), Ankh-Morpork offers an incredible variety of shops and services, among them: multiple playerbanks and player-shops, resurrection services, various post-offices