The Aztecs were the largest civilization to ever rule Mesoamerica, and they were also the bloodiest. In recent years, archaeology and modern science are shedding new light on their prolific practice of human sacrifice. Could the gruesome tales of sacrifice and dismemberment, as told in the Spanish chronicles of the 16th century possibly be true? Could 80,400 people have been sacrificed in just 4 days in 1487? Josh travels to Mexico City to investigate and use forensic science to examine the bones of sacrificial rituals. He'll try his hand at the weapons of the Aztecs, sample the potions of the priests and even cut through flesh using the technology of the ancients.