why would they have to 'get across'?
The continents were once joined, for one thing.
For another, why is it always assumed that because, for tens of thousands of years no one in Europe knew there WAS a north and south America - ergo, no other people - that, after discovery, any people here had to've come from the old world.
Why?
Why couldn't there have been people on these continents from the beginning also?
man is arrogant.
65 million years ago.