I agree to a large extent that the treaty of Versailles and other peace settlements that followed World War I, were the main causes of the world war II. However, there was also other factor that was one of the causes of World War II.
The treaty of Versailles was an unfair and a harsh treaty. The Big Four forced the German government to sign this treaty and so the government did not have any other choice. This treaty was a great humiliation to the Germans, as they had to do what the Big Four wanted.
The Germans were to take the full blame for starting the World War I and they were made to pay compensation in form of huge amounts of money and goods. Germany were also told to keep small its army and navy so that they would be too weak to fight another war. Besides, Germany lost all of its colonies and these colonies would be run by one of victorious powers until they were ready to gain independence.
The Germany new leader, Adolf Hitler, was unhappy with this harsh treaty set by the Big Four. He promised that he would reverse the terms of the treaty of Versailles. He then abolished the treaty of Versailles and he tried to bring back all the Germans into a Greater Germany. He also tried to regain lands that were belonged to the Germany. At that time, France and Britain were having economic problems and so they did not really pay attention on what Hitler had done. When Hitler tried to invade Poland, France and Britain started the World War II in order to stop Hitler from invading Poland. This showed that the unfairness of the treaty caused the World War II.
However, it was not just caused...