In 1946, an American archaeologist climbed onto a cattle pasture in southern Veracruz and counted five colossal basalt heads half-buried in the grass. The pasture was not a hill. It was the platform of the largest city in the late-second-millennium Americas. Seventeen of the heads have now been found — each one a different face, each one a person whose name is lost. They were carved three thousand years ago by people without a wheel, without a draft animal, and without a single metal tool, from stone dragged eighty kilometres across swamp and river. A sleep walk through the oldest civilization of the Americas, and the question that two hundred years of archaeology has not answered: how.