How does urbanization affect culture?

(is it because where they settle they also see other cultures and bring there cultures for others to see?)

Sometimes. However, if you study the settlement of New York over time (or San Francisco or just about any other large city), you'll find that immigrants settle where there are already people of their own culture and language. Thus there has been the development of Chinatown, Koreatown, etc., in many cities. Consider, also, the settlement of the Irish in Boston and the settlements of Germans and Italians in New York City.