An ancient Mexican city, Monte Albán, was the biggest settlement in the region and lasted for more than a thousand years. Some hypotheses for the city's success are that people were drawn to fertile farmland in the area, or were forced to move there by powerful rulers. This new study challenges those ideas by showing that the land isn't especially good for farming, and the society didn't have the highly concentrated wealth and power that would come with a powerful ruler forcing people to move there. Instead, the city had a more collective form of government that could have attracted people to the city.