When people go and live overseas, they tend to surround themselves with relics and reminders of their old lives. Feeling, in the words of science fiction author Robert A. Heinlein, “like a stranger in a strange land,” they try to make the alien landscape as familiar as possible.
Immigrants often create miniature versions of their homeland in their adopted home. It is understandable. Being used to a particular way of life, food, clothes and so on, they want to carry on in the same way rather than make a radical change to their lifestyle.
So it is that foreign enclaves come into existence. Expats worldwide like to eat their own food, speak their own language, and buy their own national products. Thus, they come together in communities, building up little quarters that resemble what they are used to.
In Europe, the Jews were long famous for sticking together as they wandered the continent to make a living.
Unfortunately, this sometimes led to resentment and unforgivable persecution from some of their hosts, the most extreme case being the Holocaust.