Westward across the Atlantic Ocean lay an altogether separate world, later known as the Americas. Although geography encouraged some interaction between African and Eurasian peoples, the Atlantic and Pacific oceans ensured that the cultures and societies of the Western Hemisphere operated in a world apart from their Afro-Eurasian counterparts. Nor were the cultures of the Americas stimulated by the kind of fruitful interaction among their own peoples that played such an important role in the Eastern Hemisphere. Nothing similar to the contact between Egypt and Mesopotamia, or Persia and the Greeks, or the extensive communication along the Silk Road trading network, enriched the two major centers of civilization in the Americas—Mesoamerica and the Andes—which had little if any direct contact with each other.

Another geographic feature that distinguished these centers of civilization from those in the Afro-Eurasian world was their rugged mountainous terrain. Sharp changes in the landscape ascending from sea level to summit gave rise to an enormous range of microclimates as well as great ecological and biological diversity. Arid coastal environments, steamy lowland rain forests, cold and windy highland plateaus cut by numerous mountains and valleys—all of this was often encompassed in a relatively small area. Such conditions contributed to substantial linguistic and ethnic diversity and to the development of many distinct and competing cities, chiefdoms, and states. It also meant that states, and sometimes individual families, sought “vertical integration,” an effort to control a variety of ecological zones where a number of different crops and animals could flourish.

Finally, the remarkable achievements of early American civilizations and cultures occurred without the many large domesticated animals or ironworking technologies that were so important throughout the Eastern Hemisphere. In the Andes, an important exception to this generalization involved the domestication of the llama and alpaca, which offered food, fiber, and transport for the civilizations of that region and in a few places provided for a time the basis for largely pastoral communities.

Accounts of pre-Columbian American societies often focus primarily on the Aztec and Inca empires (see Chapter 12), yet these impressive creations, flourishing in the fifteenth and early sixteenth centuries, were but the latest in a long line of civilizations that preceded them in Mesoamerica and the Andes, respectively. These two regions housed the vast majority of the population of the Americas. Here the historical spotlight focuses on the long period following the First Civilizations of the Olmecs and Norte Chico but preceding the Aztecs and Incas, roughly 500 B.C.E. to 1300 C.E.

The region housing Mesoamerican civilizations stretched from central Mexico to northern Central America. Despite its environmental and ethnic diversity, Mesoamerica was also a distinct region, bound together by elements of a common culture. Its many peoples shared an intensive agricultural technology devoted to raising maize, beans, chili peppers, and squash. They prepared maize in a distinctive and highly nutritious fashion and based their economies on market exchange. They practiced religions featuring a similar pantheon of male and female deities, understood time as a cosmic cycle of creation and destruction, practiced human sacrifice, and constructed monumental ceremonial centers. Furthermore, they employed a common ritual calendar of 260 days and hieroglyphic writing, and they interacted frequently among themselves. During the first millennium B.C.E., for example, the various small states and chiefdoms of the region, particularly the Olmec, exchanged a number of luxury goods used to display social status and for ritual purposes—jade, serpentine, obsidian tools, ceramic pottery, shell ornaments, stingray spines, and turtle shells. As a result, aspects of Olmec culture, such as artistic styles, temple pyramids, the calendar system, and rituals involving human sacrifice, spread widely throughout Mesoamerica and influenced many of the civilizations that followed.