Ancient American architecture more sophisticated than previously thought

The speedy construction of earthen mounds challenges assumptions about the social structure of early American hunter-gatherers.

An absence of signs of rainfall or erosion around one of the mounds in Louisiana suggests it was constructed in under 90 days and possibly as quickly as 30 days.

The results debunk the idea that pre-agricultural populations were socially, politically and economically “simple” and unable to organise themselves into large groups required for elaborate architecture and “complex” social behaviour.