Caral sits in Peru's Supe Valley, a sprawl of pyramid mounds that stayed buried under sand and scholarly assumption until archaeologists dated it to around 2,627 BC, making it as old as Egypt's pyramids and a thousand years older than any other known civilization in the Americas. The film walks the main pyramid, a mound covering roughly fifteen football fields with an estimated two million cubic meters of fill, and lays out why researchers think this could be a genuine 'mother city', a point of origin rather than a product of outside influence. Archaeologists explain the case for Caral as the missing link that might answer why humans first organized into cities and states at all. Later surveys, referenced here, found Caral was not alone: as many as twenty related settlements with pyramids and sunken plazas turn out to be spread across three river valleys, built starting around 3000 BCE and occupied peacefully for over a thousand years, with no walls, weapons, or signs of war turning up anywhere in the complex.