Teotihuacan
Learn about Teotihuacan — the massive ancient Mesoamerican city of pyramids that was one of the largest urban centers in the world by 400 CE.
Teotihuacan was one of the ancient world's great mysteries. At its peak around 400 CE, this vast city in central Mexico's Valley of Mexico held an estimated 125,000 to 200,000 inhabitants, making it one of the largest cities in the world at the time — comparable to contemporary Rome or Constantinople. Its enormous Pyramid of the Sun and Pyramid of the Moon dominated a meticulously planned urban grid that stretched for over 20 square kilometers.
What makes Teotihuacan so enigmatic is how little we know about the people who built it. The city had no known writing system (or none that has survived), so we don't know what language its inhabitants spoke, what they called their city, or what political system governed it. Even the name 'Teotihuacan' was given centuries later by the Aztecs, who found its ruins and called it 'the place where the gods were created.'
What archaeology reveals is a city of extraordinary planning and multicultural sophistication. The main avenue — the Street of the Dead — runs for over 3 kilometers, lined with pyramids, temples, and palatial compounds. Apartment complexes housed people organized by ethnicity and occupation, including enclaves of Oaxacan and Maya residents. Teotihuacan's influence radiated across Mesoamerica, shaping art, religion, and trade networks for centuries after the city's mysterious collapse around 550 CE.