The Arch of Ctesiphon
Mud brick was the most common building material in Mesopotamia, until the advent of modern concrete. Baked bricks were only used for major projects such as the arch at Ctesiphon, just outside Baghdad, part of a palace built by Sasanian kings in the sixth century AD.
The Sasanians were an Iranian dynasty, but they used traditional Mesopotamian building techniques. The arch, a huge open audience hall 30m (98ft) high and some 43m (141ft) long, should have required massive scaffolding, but the Mesopotamians leant the courses of brickwork back at an angle, so that each course was built against its predecessor, and only a mobile tower for the builders was necessary. The arch was flanked by façades decorated with blank arcading and pilasters, but the one on the right collapsed a century ago.
