Most histories focus on the Spanish swords and Aztec resistance, but the true turning point at Tenochtitlan happened in the water. In this episode, we explore how Hernán Cortés transformed his fleet from a stranded liability into a floating fortress, navigating the chinampas and canals that defined the city. We look closely at the brigantines built at Tlaxcala, the engineering marvels that allowed Spanish gunpowder to dominate the lake, and the brutal reality of cutting off fresh water supplies. You will hear about Captain Juan de Villagran’s daring raids, the strategic importance of the causeways, and how the Mexica warriors adapted their naval tactics with reed boats and obsidian-tipped spears against steel hulls. This is not just a story of conquest, but of logistics, hydrology, and desperate innovation on both sides. We examine primary accounts from Bernal Díaz del Castillo and indigenous codices to reconstruct the chaotic, muddy, and deadly battles that took place on Lake Texcoco between May and August of 1521.