MEXICO CITY - Like Paris or London you cannot drink in this city at a single sitting. You sip at it. Then you leave it for a while. Then you come back and sip again.  

For here is the oldest city in the Western Hemisphere, established in 1325 when the Aztecs, the last of several wandering tribes in the Valley of Mexico, established their city on a large island in the middle of Lake Texcoco.

The city eventually fell to the combined military action of the Spanish and indigenous neighbors in 1521. Eventually, a new city was laid out over the ruins of the old one and became the rich and complex maze that is now home to about 18 million people.

But, where do you start in a city with seven centuries of history? How do you span that enormous time gulf between now and then?

When you walk along Mexico City’s fashionable Zona Rosa, you’re overwhelmed with fashionable jewelry stores, high-end hotels, sumptuous restaurants, boutiques headlined by the houses of Gucci, Chanel, and Cartier.

Yet, you know that just beneath your feet are the foundations of what has become a living ruin - for even today, excavators are constantly digging up relics of the past -the top of a building, a golden trinket, a maze of homes.

Anywhere in the city, as you stand and look at what's left from a human civilization that was vibrant and that dated from before the birth of Christ, you wonder whatever happened to it.  For two centuries they developed a nation that extended from the Pacific to the Gulf of Mexico. And no matter where you go, you're bound to find traces of it.  

This is the home of the National Anthropology Museum at Chapultepec Park in the Paseo de le Reforma, where you can spend days traveling the time of Mexican history and play wonderful mind-games about what happened to these people over the course of history. And it’s a magnificent game, complete with hands on exhibits and golden art that staggers the imagination.

But, to really understand this city - to discover its heart - you have to take a tour bus from your hotel to outside Mexico City where, at the Pyramids of Teotihuacán, if you stand in the middle of the plaza, you can almost hear the ancient music that was once played here during festivals and celebrations.

Yes, this may be one of the most favored tourist side trips in all of Mexico, but that doesn’t matter. For the pyramids and their surrounding structures are to the Mexicans and Mexican history what the Egyptian pyramids are to that country. And you cannot understand what’s in Mexico City unless you encounter this place.

At one time, after all, thousands loved and worshipped, walked beneath and on the Temples of the Sun and The Moon, along the Street of the Dead, and in the Palace Of The Jaguar. This place has special meaning. The oldest known remnants of civilization ever found on the North American continent were found in Mexico. Teotihuacán is one of the last remnants of the inheritance of that civilization.  

Religion was the central focus here and in other Aztec centers, but it was a religion that was as much earth-bound as it was celestial.  Their gods included Macuilxoshiti, the god of music; and Xochipilli, the god of dance. Near the temples were houses of song and dance. Everyone danced, from the lowest social class to the highest.  

It’s an enormous leap in faith to move both physically and in your mind’s eye from Teotihuacán to the Mexico City where, at the plaza of the Three Cultures, are the ruins of an ancient Aztec pyramid where the Aztecs made their last stand and were finally defeated by Hernan Cortez and his conquistadors.  

Nearby are the Church of Santiago and the Convent of the Cross, both erected by the Spanish immediately after the conquest.  Every now and then, excavators digging the foundations of new buildings, discover something - gold, ruins- tiny reminders of what was once in the city.  

Elsewhere in the city, the past and the present stand side by side in what seems a natural co-existence.  And like Paris, the places that appear on your “must-see” list embrace history as a backdrop to the passions of today.

The Basilica of our Lady of Guadeloupe, one of the holiest places in Catholic Mexico, stands as a circular monument to contemporary architectural design while nearby are two other churches bearing the same name, but which have sunken into the plaza.

And the Old City - to Mexico City what the Isle St. Louis is to Paris, the old heart of the city - stands the magnificent National Palace with gigantic frescos by the artist, Diego Rivera.

The Mexican painter (1886-1957) was noted for murals that exalt workers in a style derived from Mexican folk art. And today you see them around the world - even in places like Detroit, Michigan where, in the 1930s, Rivera painted a controversial impression of assembly-line workers.
    
But, Mexico City is more than just an attractive place to experience the past. It is, like all great cities, a place for the living.

Take a ride down Insurgentes Avenue to the Ciudad Universitaria and walk among the contemporary architecture in a place where some 300,000 young people get their education.
    
Still, if you don't you understand the origin of Mexico City, there’s a good chance you’ll walk away thinking only about the traffic, the shopping, a few museums, and wonderful restaurants and boutiques.

For it's easy to believe this is a city dominated by European influences and certainly the symbols are obvious - the great cathedrals, the arts organizations, the language itself - a leftover from the conquering Spaniards.

And if you’ve been only to the beachside resorts of Acapulco, Puerto Vallarta, Mazatlan, Cancun, and Ixtapa, whatever Aztec or Mayan ruins you come upon may have seemed almost like a Disneyland backdrop to the beaches and sun.  

That's why to understand the heart and soul of Mexico you must go to Teotihuacán and climb the Temple of the Sun. From the top you look down on the huge square and up the Street of the Dead. Around you is a look back in time.  

And, the feeling you get is an overwhelming solitude - a feeling far removed from the sometimes frantic pace of Mexico City.