As agriculture increased in the fertile Coatzlcoaltl River Valley region of present-day Veracruz, Mexico, some individuals began managing resources and controlling the rich farmland, rising as the elite ruling class of early Olmec communities. The Olmecs transitioned from a non-agricultural to agricultural society around 3,000 BC by cultivating maize, squash, and beans using slash-and-burn farming techniques. This led to population growth and the development of complex intellectual pursuits including calendars, ball games, writing, construction of pyramids, and sculpting of colossal heads.