[rktman]

Probably a land bridge near Alaska? Probably some of them even went to South America.

[Larry Lucido]

That was an accomplishment, since the Darién Gap never froze over to my knowledge. They likely had some good ocean navigators, though.

[SunkenCiv]

That one’s the ultimate bridge-for-sale pitch. Clearly people in very ancient times found little impediment to travel by water. Around here, as recently as 180 years ago, water routes were often the best/quickest/only way to get around.