What was the name of the Aztec capital conquered by Hernán Cortés?

The Aztec capital conquered by Hernán Cortés was Tenochtitlan.

Tenochtitlan stood on an island in Lake Texcoco, in the Valley of Mexico, and was the political heart of the Mexica-led Aztec Empire. According to the traditional date, the city was founded in 1325. It was linked to the mainland by causeways and supplied by canals, making it both a spectacular urban center and a difficult military target.

Cortés entered the city in 1519 and initially dealt with the ruler Moctezuma II. After conflict and a Spanish withdrawal, Cortés returned with Indigenous allies, ships adapted for Lake Texcoco, and reinforcements. The siege lasted from May to August 1521. On August 13, Cuauhtémoc surrendered, and the city fell after fierce fighting, famine, disease, and the destruction of its water and transport systems.

Tenochtitlan is often casually called “the Aztec capital,” although “Mexica capital” is historically more precise. Teotihuacan was an ancient city that had declined centuries earlier, while Machu Picchu and Cusco belonged to the Inca world. Mexico City was later built largely over the ruins of Tenochtitlan.