Mexico's largest city is a sprawling metropolis of nearly 9 million people, centered in a metro area of 20 million. The city is also one of the oldest in the Americas, tracing its founding back to the Aztec city of Tenochtitlan in 1325, nearly 300 years before the first permanent English settlement in North America. The modern city, parts of which are built on top of the ruins of Tenochtitlan, is a blend of centuries of history with a modern, cosmopolitan city. One week here was not nearly enough to experience all of the city’s museums, parks, shopping, and excellent cuisine. It is a destination that definitely warrants a return trip, but is close enough to be enjoyed on a long weekend.