A huge ice wall must have blocked the road for the first Americans

The ice barrier must have measured thousands of feet high.

A 300-story ice barrier – taller than any building on Earth – could at first prevent people from entering the new world from a land bridge connecting Asia to the United States, a new study has found.

The findings suggest that the first people in the United States came by boat to the Pacific coast, the researchers said.

There are two main assumptions about how people first immigrated to North America. The old adage suggests that people made the journey when Beringia – the land that once connected Asia to North America, now divided by the Bering Strait – was relatively ice-free. Recent speculation suggests that passengers made their way across the Pacific coast of Asia, Beringia, and North America.

One of the major factors influencing the way the first Americans came is the huge ice sheet that once covered North America. Previous research suggests that the ice-free corridor in the margins of this ice sheet may have made it possible to travel from Beringia to the Great Plains.