WHEN the Spaniards arrived in the Valley of Mexico in the 16th century, they found the sprawling Aztec city of Tenochtitlán, destroyed it and built a new one on top of it. But they never really succeeded in burying the past. Mexico City became the largest city in the Western Hemisphere, a nexus of Latin American art and political thought. Today, after difficult adjustments to globalization and the precipitous devaluation of the peso from around 3 to the dollar to nearly 11 over 12 years – often cited as a cause for a spike in crimes like kidnapping and robbery – the city remains a teeming, vibrant and joyful place. Even the skies are blue again because of new laws that restrict auto use. Despite all the layers time has imposed, from the colonial past to the present day of “nuevo cine Mexicano” and “techno-rave en Español,” even a weekend visitor will still feel the spirit of the old Aztec capital ever present alongside the new.