Ancient America was a very different, undisturbed place before the time
of the "Contact", when the European explorers came to the New
World.
Cut off from a retreat to their Asian homeland by the whims of the land bridge and the ice barriers, the pioneers moved deeper and deeper into their new continent. The Native Americans moved around North America as the food supply shifted from one area to another. This geographic redistribution resulted in large part from the comings and goings of the glaciers. When the glaciers expanded, flora, fauna and people were forced southward. As the glaciers retreated and melted, they watered large areas that are now arid (e.g. the Great Basin - today’s Nevada, Utah, Colorado area). These lands supported much vegetation, many animals, and presumably people. Aridity set in when the glaciers had run their course and no longer were furnishing meltwater. As the food trail dried, people probably left these areas.
Population growth over the many millennia was slow, however in the American land of plenty they not only survived but flourished. As generation followed generation, they spread from the Central Plains to present-day California and to the forests of the Atlantic Coast. They trekked through Mexico and Central American jungles and reached the southernmost tip of South America, Tierra del Fuego. Above all, they learned to adapt to the many new environments the New World held for them.
North America
Before the European explorers arrived, the descendants of the prehistoric pioneers and later migrants - the Native Americans - had formed a wide variety of tribes in North America. Clearly, they were all related. But some of them were simple nomads, roaming the dry plateaus and deserts of the West, while others were forest dwellers who sustained themselves as hunters and fishermen. In the Southwest lived the farming people of the Pueblo country, inhabiting substantial cities of stone or adobe (clay). In the Four-Corners area of the present Utah, Colorado, Arizona and New Mexico states was the heartland of the Anasazi people - the "ancient ones". Their culture began taking on its distinct characteristics about 100 B.C., but it became by the time of its climax the most extensive and influential by far in the Southwest. Along the Mississippi were the villages of the Mound People who built giant earthworks atop which they worshipped their gods. By this time the Native Americans spoke many different languages, some as different from each other as Italian from English. More than 200 languages and dialects developed. There were great variations in customs and traditions from place to place and tribe to tribe.
Mesoamerica
The first major civilization of Mesoamerica (what stretched from Mexico’s central plateau south to Costa Rica) was that of the Olmecs, the enigmatic people who inhabited the jungles along Mexico’s Gulf Coast as long ago as 1200 B.C. Their rulers built impressive temples and spread their influence throughout Middle America, among them to the Maya, Toltec, Aztec, as well as other peoples far to north and south.
Agriculture, as part of the milestones of cultural improvements, was invented in Mesoamerica circa 7000 B.C. to 1500 B.C. and began to spread northward. To aid in the process of human geographic distribution, agriculture arrived to North America from Mesoamerica and possibly also the Caribbean between 1000 and 2000 years ago. Areas suitable for agriculture were suitable for humans. Mesoamerica, along with the Andes region of South America, where agriculture also developed, is therefore sometimes referred to as "Nuclear America".
South America
Native Americans spread out quickly in South America. They inhabited the hot and humid jungles just like the cold Andes high above the sea level, and adopted their lifestyle perfectly to the given climate and circumstances. The most spectacular culture of the area was the Inca.
