A Multicultural Society - Living in a cosmopolitan city

It is common that over the world live people together with different nationalities, colours of the skin and religious belief. When people with those differencies live together they form a multicultural society.
The term multiculturalism refers to a state of both cultural and ethnic diversity within the demographics space. As opposite we can use the term monocultural nation or state, which means state with cultural unity or cultural homogeneity.
Cosmopolitan Society/Cosmopolitan City - where people of many ethnicities, religions and cultures meet and live in close proximity.

Do you know some cities, that we can call cosmopolitan city?
F.e. New York, London, Brussels, Sydney ...
Can we talk about some cosmopolitan cities in Slovakia? Or in neighbouring countries?

Usualy different nationalities stay in their own areas inside the cosmopolitan city, they form districts and wards. In every cosmopolitan city we can find those districts. It can be russian district, chinatown, polish, portugees etc. People in those districts keep their own traditions and customs in a foreign country. Sometimes the feelings of the unity inside of those district is so strong, that they even marry only people of their own nation.
...