After AD 800 massive mound complexes appeared on the Mississippi and in adjacent regions. Although most Mississippian people dwelt in small communities, the elite of the society as well as large numbers of commoners lived in these massive regional centres, like Moundville and Cahokia.
The most striking feature of these centres, which had both a political and a religious function, are the vast platform mounds, grouped around plazas, which supported public structures and elite residences and in which the most important chiefs were buried, with elaborate grave offerings and sometimes human sacrifices.
Like their Adena and Hopewell predecessors, the Mississippian chiefdoms maintained wide-ranging trade contacts, obtaining both exotic raw materials like seashells but also basic necessities like chert for hoes and salt, a vital supplement to a diet in which maize was now the staple.
The fertile floodplains of the East were favoured lands which could support high populations. However, the annual floods upon which the farmers depended were unpredictable, so that there were not only years of bumper yields but also periods of famine.
Communities employed various strategies to spread the risk. Surplus yields in good years were stockpiled, often in communal granaries, under the management of the chief. These were available in time of need both to members of the community and to other related groups with whom kinship ties were maintained; they also provided for large feasts involving many groups by which such kinship ties were reinforced and at which trade and exchange could take place.
