The indigenous peoples of the Americas are the pre-Columbian inhabitants of the Americas, their descendants, and many ethnic groups who identify with those peoples. They are often also referred to as Native Americans, First Nations and by Christopher Columbus' historical mistake "American Indians" or "AmerIndians". According to the still debated New World migration model, a migration of humans from Eurasia to the Americas took place via Beringia, a land bridge which formerly connected the two continents across what is now the Bering Strait. The minimum time depth by which this migration had taken place is confirmed at c. 12,000 years ago, with the upper bound (or earliest period) remaining a matter of some unresolved contention.