What happened in world war 2?

The major causes of World War II were numerous. They include the impact of the Treaty of Versailles following WWI, the worldwide economic depression, failure of appeasement, the rise of militarism in Germany and Japan, and the failure of the League of Nations. ... Then, on September 1, 1939, German troops invaded Poland.

After the end of the war, a conference was held in Potsdam, Germany, to set up peace treaties . The countries that fought with Hitler lost territory and had to pay reparations to the Allies . Germany and its capital Berlin were divided into four parts. ... Austria was also occupied by the four Allies from 1945 to 1955.