It is little solace to recall that Mesopotamia was once so rich, so fertile of art and invention, so hospitable to the Sumerians, the Seleucids, and the Sasanids. The prime fact of Mesopotamian history is that in the thirteenth century Hulagu destroyed the irrigation system; and that from that day to this Mesopotamia has remained a land of mud deprived of mud's only possible advantage, vegetable fertility. It is a mud plain, so flat that a single heron, reposing on one leg beside some rare trickle of water in a ditch, looks as tall as a wireless aerial. From this plain rise villages of mud and cities of mud. The rivers flow with liquid mud. The air is composed of mud refined into a gas. The people are mud-coloured; they wear mud-coloured clothes, and their national hat is nothing more than a formalized mud-pie. Baghdad is the capital one would expect of this divinely favoured land. It lurks in a mud fog; when the temperature drops below 110 [ºF], the residents complain of the chill and get out their furs. For only one thing is it now justly famous: a kind of boil which takes nine months to heal, and leaves a scar.