[anrakushi]

i have to disagree with the OP because i can tell most of the time, especially chinese and japanese. that one is pretty easy. sometimes i have a little difficulty with koreans but most of the time i can tell.

as for westerners, more specifically europeans, you can get learn to pick up where they are from by their features as there are indeed differences. of course there is the simple fact that someone from a spanish blood line could be born in germany and then it would be difficult to know they are from germany but we are talking about their race/family heritage not their nationality.