The first cities in the Americas are generally believed to have been those of the so-called Olmec civilization in modern-day Mexico. The oldest of these cities date to around 1200 B.C., and seem to have been the ceremonial centers of chiefdoms, though some archaeologists argue that some form of unified Olmec state may have existed at some point. It should be emphasized that the earliest cities were very small, and had small permanent populations, and some archaeologists disagree as to whether they should be considered cities at all. On the other hand, the Olmecs did have a sophisticated counting system, and some form of writing, both of which point to a complex bureaucracy. The Olmec civilization was based upon the cultivation of maize, and practiced human sacrifice, as did its successor civilizations in Mesoamerica. The Olmecs are also noteworthy for large, life-like statues, which seem to have had some kind of ceremonial importance.