The need for buildings and settlements to withstand and repel attacks led to the construction of many impressive defensive structures. The formidable twin walls of Babylon were an early example of such practices. One of the seven wonders of the ancient world, its multi-layered defences were built from baked brick and reinforced by a surrounding moat. It was stated by Greek historian Diodorus that such construction took two hundred thousand men a full year to complete. On standing before them, Cyrus the Great, commander of the besieging Medo-Persian forces exclaimed “I am unable to see how any enemy can take walls of such strength and height by assault”.
