The Aztec Thing 
When I was a kid growing up in the suburbs outside New York City, everything around me was new. Our little town, a creation of the post-World War II boom, had sprung forth fully grown, like a brainless Minerva dedicated to efficient housing, alluring shopping malls, and easy-on/easy-off expressways so you could get away from it all as fast as possible.
When I was ten we moved to New Hampshire and I had my first taste of history. Two hundred year old stone walls divided the rolling countryside. Big red barns, squat Grange halls and houses with large front porches spoke of a time without cars or television, before the Blackberry replaced the rising and setting sun as the way to arrange one's time.
At 19 I moved to New York City, a place too busy rushing toward the future to be overly concerned with the past. There, the colonial heritage is kept alive mostly in museums and wood-paneled restaurants with the word 'Tavern' on the signs.
But from the first time I visited Mexico in 1989, I felt something different about the age and the history of the place, something much older, but very much alive. The reminders of both impermanence and endurance make living in Mexico City now such a rich and rewarding experience.
Tenochtitlán , the Aztec name for what is now Mexico City, was founded in 1325. By the time the Spaniards arrived in 1519 the place had grown into one of the most magnificent cities on the planet. The conquistadores tried their best to level the city, but what they mostly accomplished was a rearrangement of the stones. Even the shrine to the Virgin of Guadalupe--the most Mexican female of them all--is built over an altar to the Aztec mother goddess Tonantzín.
The ruins of the Templo Mayor, the principal site of Aztec worship, were discovered accidentally by electricians laying cables in 1978. The huge mass of stone sits right in the middle of today's metropolis, making it feel as if everything else emanates from this once sacred site. A temple to Ehecatl, Aztec god of wind, sits smack in the midst of a busy passageway at the Pino Suarez metro station. Bits of carved stone adorn several buildings in the centro historico, and things keep popping up at building sites, much to the dismay of architects and developers who must stop work and let archeologists take over. In 2010 a twelve-ton monolith of the earth goddess Tlaltecuhtil--one of a very few pieces still to retain its original colors--was found near the Templo Mayor. She's quite ugly, but displays an awesome sense of power (you can see her in the museum next to the ruins).
A vivid reminder of Aztec presence in Mexico City is the use of Nahuatl, the language of the Aztecs. You will occasionally hear it spoken in a market, but perhaps the biggest reminder of Mexico City’s Aztecan origins is the abundance of traditional, old names in Mexico City. There are more than 800 Moctezumas in the Mexico City phonebook, and numerous Cuauhtemocs. Aztec place names are found all over the city, and can be real tongue twisters at first. I managed the relatively easy Coyoacán and Xochimilco early on, but I don't think I really felt at home here until I was successfully able to tell a taxi driver to take me to Plaza Popocatepetl, Calle Iztaccihuatl and the Sala Nezahuacoyotl. (It's easier than it looks, as most words are pronounced as they would be in English, except for X which can have a 'sh' or 'h' sound, and stressed on the penultimate syllable (as in Spanish), unless there's an accent.)
Hardly a day passes in Mexico City without some reminder of the culinary heritage the Aztecs left us. Although technically anything that includes animal fat is a post-conquest adaptation, many foods in Mexico have been eaten essentially unchanged for more than a millenium--the ubiquitous tortilla is the perfect example. Corn, tomatoes, chilies, chocolate and cactus (nopales) are part of any Mexican diet. Pulque (a fermented drink made from sap of the maguey cactus), escamoles (ant eggs), chapulines (grasshoppers), and gusanos (grubs) might seem exotic to foreigners, but is familiar to any Mexican. Every time I unwrap a cornhusk to eat a tamal I get a certain thrill of being part of something much bigger, much older, than myself.
At almost 700 years and counting, Mexico City wears its age like an old movie star who refuses to get a face lift. The wrinkles, grey hair, the wear and tear--it's all part of the charm. But when she gets dressed up to go out, you might think she's been drinking from the Fountain of Youth (check out Colonia Roma on a Friday night and you'll see what I mean). The Aztec thing--earthy, pagan, hidden just below your feet, new and old at the same time--is part of Mexico City's eternal allure.