Tenochtitlan is the capital of the Aztec civilization, it was located where modern day Mexico City rests. The city appears in Age of Empires II: The Conquerors, and in Age of Empires III: The WarChiefs.
Age of Empires II
The Montezuma campaign is focused around this city and its invaders, the Spanish. The city is featured twice in the campaign. In the fourth scenario (La Noche Triste), the player controls an Aztec resistance, led by Cuauhtemoc, to regain control of the city from the Spanish. In the last scenario (Broken Spears), the player is already in control of the great city, and must defend it from Spanish and Tlaxcalan attacks.
Age of Empires III
Tenochtitlan appears as a Home City to the Aztecs, a full faction that succeeds the Aztec minor natives. When an Aztec player chooses a Home City Card that provides units, these units can be seen marching through the city's streets, before reaching the battlefield.
The city is featured as it was before the Aztec Empire's conquest by the Spanish, with canals (on whose waters lie some boats, including a Tlaloc Canoe), murals, and the (now ruined) structures intact and painted on bright colors.