Tenochtitlán was the capital of the Aztec Empire, located on an island in the middle of Lake Texcoco in present-day Mexico City. Founded in 1325, it became one of the largest cities in the world by the early 16th century, known for its impressive temples, canals, and vibrant marketplaces. The city was a marvel of engineering, featuring a complex system of causeways and aqueducts that supplied fresh water. Tenochtitlán was also a center of culture and religion, with the grand Templo Mayor at its heart, symbolizing the power and sophistication of the Aztec civilization.