Why was the historic downtown of Mexico City declared by UNESCO a World Cultural Heritage site? Very simple… Let’s start with its almost 4 square miles, within which are pre-Hispanic monuments from the time of the Aztecs, including the capital of Tenochtitlan was founded here. Subsequently with the arrival of the Spaniards, works of architecture in European style were erected as a testament of colonization. These buildings, which are still standing, date back from between 1521 and 1821. In recent years, the historic downtown has been enriched through numerous restorations, which help to preserve its magnificent colonial image mixed with the glamour of modern hotels, restaurants and fashionable businesses.