Around 2500 B.C. the Maya started cultivating corn (maize) and abandoned a nomadic way of life to settle in villages surrounded by cornfields. With the domestication of corn and the harnessing of rainwater for irrigation, all the elements were in place to support a growing Maya population. As early as 1500 BCE the Maya had settled in villages and were practicing agriculture. The Classic Period of Mayan culture lasted from about 250 CE until about 900. At its height, Mayan civilization consisted of more than 40 cities, each with a population between 5,000 and 50,000.