What happened at the sites of prehistoric burial mounds after they were erected? In the southern highlands of Brazil and Argentina the pre-Hispanic mounds of the twelfth-thirteenth centuries AD are surrounded by large circular enclosures with avenues leading to their centre. The authors discovered that the banks of the surrounding enclosure were built up over several generations of time, accompanied by a succession of ovens. Ethnohistoric observations of more recent peoples in the same region suggested an explanation: the cremation of a chief was followed by periodic feasts at his mound, where meat was steamed and maize beer prepared at the edge of the gathering.

Lands in south-central Chile, long thought to have been marginal until the Spanish conquest, are here shown to have been developing complex societies between at least AD 1000 and 1500. Part of the motor was provided by coastland cultivation on raised platforms, here identified and surveyed for the first time. The authors date the field systems and suggest that they were introduced by farmers from the north seeking wetlands in the face of increasing aridity in the central Andes and southern Amazon.