The architecture of the first cities, built in a land without stone or timber: mud brick and baked brick, buttressed walls, glazed tiles, and the ziggurat, a man-made mountain carrying a temple towards the sky.
In the alluvial plain between the Tigris and the Euphrates there was clay, reed and bitumen, and little else. The Sumerians made the first cities of the world out of these materials in the fourth millennium BC. Walls were of sun-dried brick, thick and battered; the important ones were cased in fired brick, which was costly in fuel, and bedded in bitumen. Roofs were of palm trunks and reed mats covered with earth. The monumental effect came from mass, from height on artificial platforms, and from the rhythm of buttresses and recesses on long walls.
The temple was raised on a platform from the beginning (the White Temple at Uruk, c. 3400 BC, stood on a terrace some 13 m high), and the platform grew into the ziggurat, a solid stepped tower. The best preserved, at Ur, was built by King Ur-Nammu around 2100 BC: a first stage about 62 by 43 m and 11 m high, of mud brick with a baked-brick skin 2.5 m thick, climbed by a triple stairway that met at a gatehouse, with further stages and a shrine above. Its faces are battered and buttressed, pierced with weep holes, and very slightly convex, a refinement, the excavator Leonard Woolley thought, meant to correct the eye.
Palaces were labyrinths of rooms around courtyards. The Assyrian kings of the first millennium BC (at Nimrud, Khorsabad and Nineveh) lined their halls with carved stone reliefs of war and hunting and guarded their gates with colossal human-headed winged bulls, the lamassu. The Neo-Babylonian empire of Nebuchadnezzar II rebuilt Babylon with walls, processional ways and gates of glazed brick, the Ishtar Gate’s blue tiles set with dragons and bulls in relief, and raised the great ziggurat Etemenanki that Herodotus described and the Bible remembers as the Tower of Babel.
Mesopotamia also gave architecture the true arch and vault in brick, used for drains, tombs and gateways from early times, and the idea of the city as a planned, walled whole. Its forms passed to the Persians, who conquered Babylon in 539 BC, and through them to the whole Near East.