It’s a pretty silly thing, nationality. If you flew to the center of every geographic area, you’d think there were dozens of unique races in the world. But if you walked, you wouldn’t understand the concept. The changes in color, face shape, hair, lips, eyes, etc. are so gradual — in every direction — that it would become obvious to you that we are all the same race.
Of course, you’d have to be a strong swimmer and climb a lot of mountains. Which is why we think there are unique races; the mountains, rivers, lakes, oceans and other geographic separations tend to keep people in one place for so long that they take on the characteristics of that area.
For example, if it’s hot, your skin and eyes will darken. Successful families, especially early in our evolution, dominated the other physical characteristics, so larger areas developed common traits. A good example would be Asia, where epicanthic folds around the eyes are a strong identifying feature.
Another is the brow bone, willed to us from the extinct Homo neandertalis. Every human being on the planet who descended from ancesters who left Africa has a prominent brow bone as part of the 2-4 percent of our dna that comes from the Neanderthal race, mixed in when the two races lived in the same area — current theory places them together in the Middle East, roughly 50,000 years ago — and intermingled. This is why native Africans lack the brow. For illustration, Manut Bol and Grace Jones are native Africans.
Globalization will eventually lead to some homogenization, but it’ll take thousands of years and I doubt the effect will ever fully wash out. There will always be a variety of shapes, sizes and colors. And family will always be family.
But (hopefully) we can stop thinking national borders are anything but man-made shock collars, and stop building false walls to keep ourselves apart.