Today considered one of the safest cities in Mexico, Mexico City is unquestionably one of the world's great metropolises. It's not its bigness however, that makes Mexico City one of the world's great cities, but rather its status as unique center of art and cultural with its multitude of galleries, museums, historical attractions and fantastic anthropological sites. Dating to its ancient Aztec civilizations, through Spanish colonization and into the modern era where diverse artists and authors have found inspiration from Diego Rivera and Frida Kahlo to William S. Burroughs and the Beat Generation, Ciudad de México is a city for the ages. One can spend months in Mexico City and still just scratch the surface of what it has to offer. This is not a pass-through city, it should be at the top of anyone's list for places to see in Mexico.
Quite literally, Mexico City is the oldest, continuously inhabited city in the western hemisphere. The history here doesn't just begin with the arrival of the Spaniards in 1524, or even with the dry lake bed that was originally settled by the Aztecs in 1325. The history of Mexico City goes back some 2,000 years as evidenced by the nearby ruins of Teotihuacan.
The entire history of Mexico is here for you to see before your eyes. Old Aztec ruins which were built over keep being unearthed in the heart of the city. Teotihuacan, just 30 miles north of Mexico City, is a 2,000 year old civilization that once rivaled the Roman empire. The scale of the pyramids here are rivaled only by the great pyramid of Cheops in Egypt. Indeed, Mexico City's National Anthropological Museum has rooms divided by dates and civilization (Mayan, Aztec, Toltec, Olmec, etc.) and that is another MUST SEE which will take you a full day all by itself.