After World War 2 there was a need to make European countries work together and build better relationships. What is now the European Union grew out of that need and it has helped to make Europe more stable.
world war 2
The European Union did not exist during World War II. It ended in 1945. What was then called the European Economic Community was founded in 1957 by 6 countries. They were West Germany, France, Italy, Belgium, The Netherlands and Luxembourg. It is now known as the European Union and has 27 members.
Jean Monnet
The European Union was set up with an aim of ending the frequent and bloody wars between neighbours, which culminated in the Second World War. The second world war is now over therefore they are not exactly fully needed
Yes World War 1 is a European War.
The United States and the Soviet Union disagreed about how European countries should be governed.
I'm not sure this will answer your question, but the European Coal and Steel Community was formed after World War II. Several countries in Europe, notably France and Germany, united to rebuild after the mass destruction of the war. This union would eventually evolve into the European Union, and the European Monetary Union (or Economic and Monetary Union; it goes by different names) This economic and political union helped to rebuild and unite the European countries who were still suffering from recent conflicts, and would also succeed in preventing intra-continental war.
go to the communist side
Germany and the Soviet Union invasion of Poland in Sept. 1939
One reason that the European Union was created was to ensure unity and safety within Europe. Europe had just been through two devastating wars (World War I and World War II), and was in the mix of the Cold War. All these wars were traumatizing to Europe, and to avoid anything like this in the future, several European countries took the initiative and formed an organization to create economic unity, which would eventually grow into something much larger and powerful: the European Union.
In World War 1 (1914-18) there were no concentration camps. For the Nazi concentration camps, see the related question.
If you mean the European Union, that would be from the start. They put the foundations of it just after the Second World War.