After AD 1400 the entire fertile expanse of the American Bottom (which at the city’s height had contained perhaps as many as 40,000 people), along with the territory from Cahokia up to the Ohio River, became what’s referred to in the literature as the Vacant or Empty Quarter: a haunted wilderness of overgrown pyramids and housing blocks crumbling back into swamp, occasionally traversed by hunters but devoid of permanent human settlement.
