Nomads are people who travel all the time searching for food
Glaciers are huge sheets of ice
Nomads walked across to North American from Asia when once the sea level was low because a lot of water was in the form of ice.

About 10,000 years ago, ice started to melt and sea raised.

"America" comes from "Amerigo Vespucci", which means the first people came back from New World.

After nomads settled down in villages, they began to farm crops.
Division of labor means people work different jobs.

Olmecs lived in 1200 BC, in Mexico. They built stone temples, statues, calendar, writing system.

Maya lived in 250 AD, in Central America. They built large temples, dug ditches, and stone courtyard. They also planted corn and tomatoes, formed cities, and 360-day calendar.

Incas lived in 1200 AD, in South America. They built step-like level farming land, roads, and palaces. They also built bathrooms with ruuning water, planted crops on mountain sides, and mined gold

Aztecs lived in 1400 AD, in Mexico. They built capital city, Tecochtiitlan. They also invented written language and math.