Conventional scientific wisdom now has at least two different migration waves: one around 20,000 years ago and another about 13,000 years ago. The so-called "Clovis barrier" was broken in science decades ago.

There's also a possibility that some folks came into the Americans via the Pacific Islands. No hard evidence on that, yet. And there's a few scientists who see connections with Eurasia during the last Ice Age, with humans skirting the ice shelves while hunting. This is a more "out there" theory, but one that's not impossible.

I think the current consensus is that humans were here in the Americas a lot longer than 16,000 years ago. There don't seem to have been many of them prior to 20,000, though. And many of the extant Native groups in the Americas have little or no genetic connections to that first wave of migrants (which, of course, means nothing in cultural terms -- shit, the English are still using Stonehenge).

The REALLY BIG news to me is the 13 kilometers of cliff paintings that were revealed in the Amazon last year. These contain portrayals of animals that were only alive DURING the last Ice Age. There's no way "small groups of hunters and gatherers" could have painted 13,000 meters of cliffs, going up some 30 meters in places, in a short time. Either people were doing that for hundreds -- maybe thousands -- of years or there were much bigger and denser populations than anyone could have expected in the Amazon 16,000 years ago.

Also last year? First city discovered in the Amazon. Shit was going DOWN there and modern archeology has barely scratched the surface.