Introduction to Teotihuacan Civilization: The Teotihuacan Civilization began around 200 BC, an ancient Indian civilization about the same time as the Mayan Civilization. Between 1 and 150 AD, the Teotihuacans built a city with a population of approximately 50,000, which can be called the earliest urban-level settlement in the entire Americas. During this period, they established a primary-scale city centered on the north-south "Road of the Dead". The buildings were mainly pyramids and temples. The development of the entire city and civilization reached its peak in 450, and the population could Between 125,000 and 200,000 people. However, it declined due to unknown reasons between 650 and 750, and finally disappeared without a trace.