The 19th century period meant economic, political, and cultural expansion for the United States. The immigration processes that have been present throughout the century have marked the United States, making it a great melting pot, especially because of European immigrants. New York was the first step into a new nation, a city where the vast majority of immigrants passed on their way to the other parts of the United States. But New York was also the city that immigrants shaped and created, forming a metropolis and largest city of the United States. Throughout the various stages of the 19th century, the United States had different regulations regarding immigration. But as a country, the United States were always in need of a large number of labor force, coming from Europe and other parts of the world. Immigrants left Europe mostly for economic reasons, but also because of various persecutions, wars and natural disasters. Immigrants in New York were faced with new challenges that they had not encountered in their home countries, from the arduous journey to the life and work in New York where they had to learn to live with people of various backgrounds and statuses. The waves of immigration are divided into two major ones. These waves are also a clear indicator of how and at what rate which part of Europe was developing or was facing economic and social problems. Four large groups of immigrants marked these stages. The first wave, with German and Irish immigrants who, along with the first immigrants from the colonial era, created the political and social foundations of the city, and the second wave with the Jews and Italians who had "built" and culturally marked it to this day.