I don't recall where exactly he was found. Mostly what I remember was discussion about his age, which is what gave the idea that he was European more significance, as he was far too old to be some ancient Greek or Roman who had somehow managed to make it across the Atlantic, and would have actually pre-dated the Natives in the region.Ah, ok.
I vaguely remember the Kennewick Man issues from an anthro class I had, where they used it as an example of how NOT to do anthro work.
As for the one in South America, do you remember where?
Because they've found Roman shipwrecks off the coast of Brazil which likely ended up there because of storms off the West African coast (Morocco was a big Roman industrial area for clay urn/vessel making). It's not inconceivable some Romans or other Med people found thier way to S. America by accident, and stayed because they couldn't return home.
Same with the Zuni and how it seems they likely interbred with some Japanese Buddhist monks who somehow ended up in the Gulf of Cali centuries before Europeans got to the area.
Then there's the whole Polynesian/S. America issue where it seems the Polynesians might have had some presence on the west coast of S. America for a time.
Sorry, little bit of a tangent there regarding some of the lesser known situations where 'non Natives' made it to the America's and may have interbred with the locals before the Europeans got here.