Imagine a 12th-century metropolis larger than London or Paris, with towering earthen pyramids, astronomical observatories, and up to 40,000 people. Now place it not in Europe or the Middle East, but in the American Midwest, across the river from modern St. Louis.

This episode explores Cahokia, the largest pre-Columbian city north of Mexico, and the rapid urban big bang that built it around 1050 CE. We trace the staggering hand-powered engineering, the social inequality baked into its food supply, the brutal political theater that held it together, and the cascade of crises that emptied it entirely.

• The 55 million cubic feet of earth moved by hand in 50-pound basket loads to build 120 engineered mounds
• How a diet shift away from nixtamalizing maize led to pellagra and malnutrition among the working class
• Monks Moun ...