the beginning of American history,

we think 1776, with the Declaration of Independence,

or maybe 1492, when Columbus arrived in the Americas.

But the history of America really begins

about 15,000 years ago,

when people first arrived in the Americas.

In this video, I want to provide a very brief overview

of native societies before contact

to give you an idea of just how diverse

and complex these societies were,

as native groups adapted to

and interacted with their environments.

Now there's recently been a scholarly debate

about how people first arrived.

We know that maybe 12,000 years ago,

during an ice age, the sea level was lower,

and so a spit of land in between

the Americas and Asia was exposed,

over which people may have traveled.

But recent archeological evidence suggests

that people were perhaps already in the Americas

at the time of this ice age,

so it's possible

that they may have come earlier in boats.

Now however it was that they arrived,

they spread north and south

and east throughout the Americas

so that by the time that Europeans arrived in the late 1400s

there were perhaps 50

million people.

That's kind of a mid-range number for the estimates,

that historians have made,

living in the Americas.

And of those, four to six million

were living in North America.

So how did these societies develop?

Well, a really big moment was around 5000 BCE,

when people in Mexico domesticated corn,

maize, as it's also known.

And domesticating maize meant that people

who had originally been hunters, gatherers,

following herds of animals

could partake in settled agriculture.

So they could develop villages, complex societies.

This isn't to say that they stopped hunting or gathering,

but they began staying in one place.

So let's zoom in a little bit and take a look

at some of the major societies in these regions.

Native American societies developed

around their natural environments,

using the resources that were available to them.

For example, the Southwest, Plains and Great Basin

were quite dry.

A lot of desert.

And so societies in these regions

adapted to the dry climate in several ways.

For example, Native American groups

that lived on the Great Plains

continued their hunting and gathering way of life.

Hunting bison,

and following the herds of animals

in teepees,

which were dwellings that were easy

to set up and then take down.

People in the Southwest, like the Ancestral Puebloan people,

dealt with this dry environment

by creating very complex irrigation projects

so that they could water their maize crops

using what little moisture there was.

The Puebloans lived in large cave complexes

as agriculture allowed them to grow their population.

In the Northwest, fishing in the Pacific Ocean

gave Native Americans a plentiful source of food,

while farming allowed the Mississippian peoples

to develop large settlements, like Cahokia,

near modern day St. Louis, which, at its peak,

may have had as many as 25,000-40,000 residents.

The Mississippians and other East Coast native peoples

relied a lot on what's known as three-sister farming,

in which people would plant corn, beans and squash together,

which was mutually beneficial to all three plants,

as the corn served as a trellis for the beans,

and the squash protected the root system of the corn.

All three together create a very nutritious diet,

which allowed for a relatively high population density

on the East Coast.

So by the time that Europeans began to arrive

in the late 1400s and 1500s,

native societies had been evolving for over 14,000 years.

But the introduction of European people, pathogens,

plants, and animals would introduce

an unprecedented amount of change in the Americas.