Many who visit Mexico City compare it to the greatest cities in Europe, perhaps because its downtown is layered in 1,000 years of culture, with one civilization built upon another. Ancient ruins, their golden stones etched with prehistoric carvings, lie uncovered at the Templo Mayor, once the thriving center of the Aztec empire. Spanish colonial churches and the Metropolitan Cathedral stand nearby, their intricate Baroque façades adorning one of the world's largest plazas, the Zócalo. Mexico City is building its future, too, with a gleaming business district, international cuisine, and world-class shopping.