c. 13,000 B.C.E.     The first immigrants arrive on the North American continent and gradually migrate in groups throughout North and South America. Neither the timing of the first migrations nor their origins are known.

c. 400 C.E.     The Anasazi culture emerges in the Four Corners region of present-day Arizona, New Mexico, Utah, and Colorado. The Anasazi, thought to be the ancestors of the Pueblo, Zuni, and Hopi Indians, were known for their basketry and pottery as well as their elaborate mansions built into high cliff walls.

c. 700     People of the moundbuilding Mississippian culture build the city of Cahokia near present-day East St.

Louis, Illinois, about five square miles wide, and containing about a hundred mounds situated around central plazas.

1000     Norse explorer Leif Eriksson sets out from Greenland and apparently sails to Vinland, in present-day Newfoundland, Canada.

1492     Navigator...