Do you know of any countries where 'proper' borders exist, other than those between East and West Germany, and North and South Korea, which existed for political reasons and economic reasons?

Or the one between the USA and Mexico, which has more to do with a dislike of the racial makeup of those wanting to cross into the USA?

Isn't a border nothing more than a line drawn in the sand patrolled by armed men in places where it is feasible?

If animals can cross borders at will, then why can't humans also? After all humans are a peculiar breed of apes without fur?