Siege of Tenochtitlan Begins — 75-Day Urban Battle

Cortés launches his reconquest with a fleet of 13 brigantines built in Tlaxcala, carried overland, and launched on Lake Texcoco. He is supported by 200,000+ indigenous allies, primarily Tlaxcalans. Cuauhtémoc, the new Aztec emperor, organizes a tenacious defense. The Spanish systematically demolish buildings and fill canals as they advance street by street. Starvation, disease, and water shortages ravage the defenders. The siege and urban warfare last 75 days, one of the bloodiest battles in pre-modern history.