By 14,000 years ago, the Ice Age was winding down.

20,000 years ago, the world suffered in the depths of the last ice age.

The Ice Age has come and you don't have central heating in your cave.

This is the ice starting to freeze over. The snow fence they built.

Some populations probably didn't survived the ice age and those that did often became more isolated from other groups, scattered around the world, these small populations became more being culturally, and genetically distinct from one another.

The ice age not only created barriers, it also created bridges with so much water locked up in ice, sea levels dropped, exposing land and connected Siberia and Alaska, a few people in Siberia took advantage of this bridge, moving into present day Alaska, and later, down into other parts of North America, maybe they followed migrating herds or maybe, they traveled in small boats, down the Pacific coast, or maybe they did both.