The first people who populated the Americas

Many thousands of years ago, not a single human being lived in the Americas. This only changed during the last Ice Age. It was a time when most of North America was covered with a thick sheet of ice, which made the Americas difficult to inhabit. But at some point during this time, adventurous humans started their journey into a new world....
http://www.bbc.com/earth/story/20170328-the-first-people-who-populated-the-americas