Why the shape of the Americas was bad for human settlement
There's still a lot we don't know about the first human
colonization of the Americas, particularly the exact timing, but
we do know that it took tens of thousands of years for humans to
make it from Alaska to Chile.  That's a long time, and the
archaeological evidence indicates that the spread of populations
and technologies in the ancient Americas was far slower than
than in Eurasia, a much larger landmass. One theory is that the
orientation of the continents is actually a factor here - while
Eurasia is primarily an east-west continent, the Americas
largely extend north-south, with Central America a particularly
good example of an area where there's very little land to the
east or west of any given position.  This may seem like a
trivial point, but there's a big difference between being able
to move into lands that are on the same latitude and being
forced to move north or south. Areas that are on the same
latitude are likely to have much the same c