Humans arrived in North America at least 15,000 years earlier than we thought, discoveries show -- which suggests they came by boat

Mads Thomsen Archaeologists have long debated when and how the first people made it to North America from Asia. Researchers previously thought early humans crossed the Bering land bridge from Siberia to Canada 13,000 years ago. But artifacts discovered in a Mexican cave shift the timeline, revealing people may have been in North America 30,000 years ago. The land bridge was impassable at that time, so the research suggests the first Americans arrived by sea. Visit Business Insider's homepage for...