Teotihuacan Collapses
Around 650 AD, Teotihuacan, one of the largest cities in the ancient world, entered a violent and decisive decline. Located in the Basin of Mexico northeast of modern Mexico City, it had been the dominant center of Mesoamerica for centuries. Its fall reshaped the political and cultural map of the region and left behind ruins so impressive that the Aztecs, arriving many centuries later, revered them as a sacred place where the gods had created the world.
Teotihuacan rose to prominence in the first centuries AD, after a population shift into the basin that may have been spurred by the eruption of the volcano Xitle to the south. By about 400 to 500 AD it likely held well over 100,000 people, though estimates vary. The city was laid out on a planned grid along the broad Avenue of the Dead, anchored by the Pyramids of the Sun and the Moon and the Temple of the Feathered Serpent. Thousands of apartment compounds housed residents, many of whom were obsidian workers and craftspeople. Its trade and influence reached the Maya lowlands, the Gulf Coast, and beyond, and Teotihuacan-style art and architecture appear at distant sites such as Tikal and Kaminaljuyú.
The collapse itself is known mainly through archaeology, since Teotihuacan left no deciphered written history. Evidence of fire is concentrated along the Avenue of the Dead, affecting temples, palaces, and elite buildings, and sculptures appear to have been deliberately smashed. This has led many researchers to see an internal uprising or a targeted destruction of the ruling institutions. Others point to foreign invasion, though evidence for it is thin. Climate stress, including drought, and growing inequality or strain on food supplies in the preceding decades have also been proposed. Most scholars favor a combination of causes, and the exact date and sequence remain debated. The city did not vanish overnight, and a reduced population continued to live there for generations.
Many former residents dispersed to other parts of central Mexico. Regional centers such as Cholula, Xochicalco, and Cacaxtla grew in the following centuries, and Teotihuacan's artistic and religious traditions continued to influence them. The loss of the city's central authority broke up established trade networks and opened the way for a more fragmented political landscape, in which rival city-states competed for power. Later, the Toltecs and then the Aztecs would build their own dominions in the same region.
Today, Teotihuacan is a UNESCO World Heritage Site and one of Mexico's most visited archaeological destinations. Its true name, language, and the identity of its rulers remain uncertain, which keeps the city one of the great puzzles of the ancient Americas.