Not just the USA, the whole American continent is one big exception to that homogeneous countries rule. But if you were to single out a single country, it shoul

Not just the USA, the whole American continent is one big exception to that homogeneous countries rule. But if you were to single out a single country, it should probably be Brazil instead, being by many accounts the most heterogeneous country in the world. Fun fact: in the fake passport circles, "Brazilian" is a popular go-to nationality because no one will question a Brazilian nationality based on your face/race/color.