One of New York's geographies has developed from its heady immigrant past. The cultural diversity of New York City has emerged due to the immigrant process that occurred. From around 100 years after the foundation of the United States, there was an open-door policy on immigration. Many Europeans were attracted due to the events occurring in Europe (war), and cheap land and the many jobs were also available in the US. More can be in the Lower East Side section.

A good reading source is: Ethnic and Racial Studies Vol.24 No.4 July 2001 pp549-577:Theorizing Transnational immigration: a critical review of current efforts. Peter Kivisto.

Also another good source about Jewtown can be found here:

http://www.cis.yale.edu/amstud/inforev/riis/chap10.html