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.