Wheat and barley moved beyond the Middle East to Europe, reaching Greece by 6000 B.C.E., Central Europe by 5000 B.C.E., and parts of western Europe by 4000 B.C.E. Similarly, maize cultivation widened in all directions from the Tehuacan Valley. By 2500 B.C.E., Indians were growing it elsewhere in Central America, in the Amazon River basin, and as far northward as what is now the American Southwest. In other cases, whole societies of farmers invaded new lands, subordinating or expelling hunter-gatherers. For example, southern Chinese rice farmers took over favorable lands in northern China and Southeast Asia.
