answer:Medieval European cities were arranged in a circular fashion around a smaller original settlement, which was itself built in a rough circle around a defensible central position such as a castle or an earthen berm. Buildings were built up against each other over a period of centuries or millenia without any intentional central planning. In North America, the original cities and towns were massacred and destroyed (or left completely deserted as disease raged ahead of the European conquerors), and new settlements built from scratch over top of the corpses and graveyards of its victims.