Teotihuacan
Teotihuacan was the largest city in the Americas before 500 CE. Its monuments were built over 350 years. Its central structures were burned around 550 CE. It housed ~100,000 people — 80–90% of the Valley of Mexico’s population. It ended between the 7th and 8th centuries CE. We know none of its rulers’ names. We do not know why it burned. We do not know what its people called it.