Tenochtitlán (tānōchtētlänˈ) [key], ancient city in the central valley of Mexico. The capital of the Aztec, it was founded (c.A.D. 1345) on a marshy island in Lake Texcoco. It was a flourishing city (with an estimated population of between 200,000 and 300,000), connected with the mainland by three great causeways. These ran along massive dike constructions erected to prevent the salty floodwaters of the eastern lake from mingling with the freshwater surrounding the island city. The dikes thereby protected the unique system of lake agriculture known as chinampas. Canals within the chinampas served to convey traffic throughout the city, including to and from the bustling, highly organized market at Tlatelolco. The ceremonial precinct contained many structures, including a great pyramid sacred to the Aztec war god Huitzilopochtli. It was to Tenochtitlán and the court of Montezuma that Hernán Cortés came, and it was from Tenochtitlán that the Spanish fled on the night of June 30, 1520, under heavy Aztec attack—the so-called noche triste. Cortés returned in 1521, took the city after a three-month siege, razed it, and captured the ruler, Cuauhtémoc, successor to Montezuma. The Spaniard founded present-day Mexico City on the ruins.
See studies in the Handbook of Middle American Indians, ed. by R. Wauchope (13 vol., 1964–73); M. P. Weaver, The Aztecs, Maya, and Their Predecessors (1972); E. M. Moctazuma, ed., Great Temples of the Aztecs: Treasures of Tenochtitlan (1988).