Chapter 2 : The First Americans The first Americans traveled from Asia to the Americas across a land bridge-and possibly the Pacific Ocean-during the Ice Age. Their descendents were the Native Americans, who developed many different cultures. The Anasazi and the Mound Builders were the major early cultures in North America. Later cultures are divided into 10 groups according to geographic location: the Arctic, Subarctic, Northeast Woodlands, Southeast, Plains, Southwest, Northwest Coast, Plateau, Great Basin, and California. In Mexico, Central America, and South America, the Maya, the Aztec, and the Inca developed advanced civilizations.