Spotted in "Girls" by the Beastie Boys on the album "Licensed To Ill"
Essentially is referencing everywhere in the world. From Mid-Western of the US' White Castle Fast Food all the way to the Nile River in Africa.
Ad-Rock: I like the way that they walk
And it's chill to hear them talk
And I can always make them smile
From White Castle to the Nile
Girl: I get looks every time I go out, from White Castle to The Nile!
When someone of any color hangs out with white people so long that their speech, style, and food preferences no longer indicate their heritage. Perhaps a more offensive way to say "Americanized".