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.
The Light Fantastic: (Discworld Novel 2) (ed. Random House, 2009) - ISBN: 9781407034393