Ankh-Morpork! Pearl of cities! This is not a completely accurate description, of course — it was not round and shiny — but even its worst enemies would agree that if you had to liken Ankh-Morpork to anything, then it might as well be a piece of rubbish covered with the diseased secretions of a dying mollusc.
Terry Pratchett (2012). “The Wit and Wisdom of Discworld”, p.16, Harper Collins