Historically, modern immigration began in the 18th century, accelerated by the slave trade and industrialization. At this time, three main types of immigration began to emerge: labor migration, refugee migration and urbanization. Since the USA gained independence in 1776 while imperialism was still dominant in Europe, many people immigrated to the USA in the early 19th century, which was considered the land of unlimited opportunity.
The beginning of the 20th century, with the fall of the great colonial empires and the First World War, also left its mark when people from Europe immigrated, driven by fear of war and violence. The aftermath of World War I was the fall of colonialism and the formation of the League of Nations. At this point, an influx of immigrants from the former colonies began, resulting in large numbers of immigrants from the newly independent countries of Africa, the former colonies of France, Great Britain, Spain and the Netherlands.
The League of Nations failed to prevent World War II. The birth of Nazism in Central Europe in the 1930s played a crucial role in immigration, as many Jews began migrating from Europe before the outbreak of World War II. After the Second World War, the United Nations Organization was founded, which has been a peacekeeper around the world ever since. The roots of the European Union also go back to the late 1940s when the Treaty of Paris was signed.
Since then, the principle of freedom of movement has developed rapidly. The newly created Schengen area in Europe allowed the citizens of its member states to move freely without border controls. The United Nations and many countries have ratified treaties on the free movement and granting of asylum to refugees. However, over the past three decades, governments have become very concerned with the problems of terrorism, human trafficking and drug trafficking. As a result, many countries have had to reduce the simplicity of their immigration policies to improve their internal security.