Archaeologists have rewritten the history books over when humans first arrived in the Americas, shifting the date of the initial migration 15,000 years back in time.
Excavations in a cave in Mexico called Chiquihuite revealed archaeological evidence of human occupation dating back up to 27,000 years.
But computer analysis further pushes this date back, with the study claiming people first lived in the cave around 33,000 years ago.
This contradicts the widely accepted belief that humans did not reach North America until around 16,000 years ago.
Academics agree that humans most likely migrated from Asia to the Americas via a land bridge across the Bering Strait, which is now underwater and forms the sea between Alaska and Russia.
However, during the Ice Age, which started around 33,000 years ago and lasted until around 16,000 years ago, this route was blocked by glaciers.
It was previously thought that people first crossed over to the Americas after the ice age, when the glaciers had melted, and most of the archaeological evidence discovered before now supports this theory.
However, the Chiquihuite cave indicates humans had already been on the continent for millennia.
The researchers propose two possible explanations for how people first colonised North America more than 30,000 years ago.
Firstly, humans from North-East Asia may have crossed over the land bridge at the Bering Strait before the Ice Age when there was a gap between the Laurentide Ice Sheet and the Cordilleran Ice Sheet.
Alternatively, they could have travelled by boat from Asia, following the Pacific coastline, until they had bypassed the glaciers.