The city that served as the capital of the Aztec Empire was Tenochtitlan, located on an island in Lake Texcoco in present-day Mexico City. Founded in 1325, Tenochtitlan became a powerful urban center and a marvel of engineering with its complex canals, causeways, and impressive architecture, including the grand Templo Mayor. The city was a hub of cultural, economic, and political activity, reflecting the sophisticated society of the Aztecs. Its fall to Spanish conquistadors led by Hernán Cortés in 1521 marked a significant turning point in world history, leading to the decline of indigenous civilizations in the Americas.