It is believed that the American continents were populated with between 70 and 90 million people at the time of European contact: about 9 million in America north of present-day Mexico; 30 million in Mexico; 11 million in Central America; 445,000 in the Caribbean islands; 30 million in the South American Andean region; and 9 million in the remainder of South America.

How the First Americans Arrived

Scientists conclude that the indigenous people of the Americas probably migrated from eastern Siberia partly because of the physical characteristics of these Native Americans. They belong to the same human stock as modern Japanese, Koreans, and Chinese. The skin, eye, and hair color, broad face, and high cheekbones of many Native Americans are most like Mongoloids, a race indigenous to eastern Asia. Scholars have concluded that decreasing rainfall in eastern Asia reduced food resources, causing native peoples to move east for survival.

The Great Ancient American Civilizations

As these nomadic Asian hunters roamed southward, some 15,000 miles from Alaska to the Tierra del Fuego at the stormy tip of South America, they split into many different tribes, developing thousands of different languages and unique cultures. Among the great ancient American civilizations were the Aztecs in Mexico, centered around the city of Tenochtitlán, which today is Mexico City; the Incas in Peru, who numbered 7 million at their height; and the Maya in the Yucatán and Central America.

A prime motivating factor for the Spanish conquistadores (conquerors) was their interest in siezing great quantities of precious metals such as gold and silver. Since the Mayan lands were poor in these resources, they held comparatively little initial interest for the Spanish, who were attracted instead to central Mexico and Peru by promising reports of the greater rewards. Within a period of fifteen years, the Spanish conquistadors Hernando Cortés and Francisco Pizarro gathered untold riches while conquering two native empires, the Aztec and the Inca.