During the Ice Age, scientists believe people first came to the Americas from Asia by walking across a natural land bridge called . Others may have sailed from Europe. They were called . By 10,000 BC, glaciers melted, oceans rose, and land bridges disappeared. As early as 7,000 BC, scientists believe farming began.
The Olmec and the Maya
Farming allowed the Olmec culture to grow in specific areas, such as government, education, religion, and architecture. The Olmec were one of the first groups to develop its own in the Americas. The were an early civilization in southern Mexico and Guatemala. For unknown reasons, the Maya left their cities and pyramids behind.
The Mound Builders and the Anasazi
The Adena, one of the first groups of , were known for the large mounds they built to bury their dead. They also built mounds for reasons. In later years, the Hopewell settled in the Ohio River area where the Adena had been situated and continued the tradition.
Later still, a third group, the , lived along the Mississippi. In the Southwest, culture flourished from about AD 200 to 1300. They lived in cliff homes on the sides of canyons and
farmed the desert using .