In the southeastern part of the United States, the Hopewell culture emerged about 100 BC. The Hopewellians built large earthworks and engaged in trade over a large region. There is evidence for significant social differentiation. Around AD 400, however, the Hopewellian interaction sphere collapsed. Nevertheless, complex social organisation once again appeared in this general region with the emergence of the Mississippian tradition that lasted from AD 700 to 1500. Again, the increased tempo of social life is indicated in far-flung trade networks, building of large structures and the existence of social hierarchy. The town of Cahokia became the capital of a full-blown state. It covered 2000 acres with houses and had a population of some 30,000. The peak of its development spanned the two centuries 1050 to 1250, and its rulers caused to be built enormous earth mounds. Cahokia shows evidence of planning and it was evidently built by by a hierarchical society with centralised control of resources. There were several other large towns flourishing at the same time and urban living in the Mississippi valley seems to have peaked around 1250. After that the Mississippian culture went into decline, more than a century before Europeans were to set foot in the region, in the late sixteenth century. At Cahokia, building work ceased in the fourteenth century and it had been abandoned completely by AD 1500. The other centres were deserted at around the same time. When Europeans arrived they found only simple, autonomous tribal groups practising agriculture which they supplemented with hunting and gathering. There were no towns or powerful chiefs masterminding the construction of monumental earthworks. Like the Hopewellian decline of about a thousand years earlier the disintegration of the Mississippian culture has not been satisfactorily explained. It is apparent meanwhile that the Mississippian culture had some continuity with the Hopewellian. Hopewellian traditions persisted on the Gulf coast and were subsequently transmitted to the emerging Mississippians. In other words, the region went into a dark age which subsequently lifted, rather than one people and culture being completely wiped out to be replaced by entirely different ones. Furthermore, like the southwest, the story of the southeast is one of fluctuations and shifting fortunes of different regions. On the Delmarva peninsula, for example, the archaeological record shows periods of culture change interspersed with periods of equilibrium. Here, status differentiation and exchange networks emerged and evolved continuously from 800 BC, to AD 900. By 1000, however the more flamboyant and developed cultural traits had disappeared and given way to the simpler lifestyles of the so-called Woodland II period.