The so-called war to end all wars, the First World War, did not solve any of the problems which had caused it. So, some years later started another world war.
The Second World War was the largest and the most violent armed conflict that opposed, between 1939 and 1945, the Allied countries with a democratic ideology countenance to the Axis coalition with a totalitarian character.
In the beginning of the war, the first block consisted of the United Kingdom (with the British Empire), France (with the French Empire) and Poland. But, with the war continuation, more countries joined to that block, such as the United States of America, China and the Soviet Union.
The war was started by Germany, but later was joined by Italy, Japan, Hungary and Romania, making the Axis Powers block. However, in the beginning of the war until its invasion by Germany, the Soviet Union also belonged to the Axis.
The main causes of the conflict are related to the agreements made after the First World War, the policy of appeasement, which was directed by the United Kingdom and France after the First World War and the expansionism of Germany and Japan.
After the Versailles Treaty, Hitler and the Nazis assumed control of Germany by calling for a heroic mass effort to restore past glory allied to the humiliating situation that treaty had put Germany and its people. After the First World War, the German economy was too bad also due to the war fines that were imposed by the victorious nations and also due to the Great Depression.
As referred, the appeasement policy was one of the major causes for the war. The British and French politicians followed a policy that gave Hitler the conditions to reinforce his position within European countries, but also gave the Germans time to rearm, being able to reoccupy Rhineland and after that launch the Blitzkrieg (Lightning War) against major part of Europe.
In Asia, Japan's efforts to become a world power and the rise of militarist leadership (in the 1930s, the government in Japan was undermined as militarists rose to power and gained de facto totalitarian control) led to conflicts first with China and later the United States of America. Japan also sought to secure additional natural resources, such as oil and iron ore, due in part to the lack of natural resources on Japan's own home islands.
So, we can list the main causes for the war:
- Versailles Treaty;
- Appeasement Policy;
- Great Depression;