First, there was the discontent of Germany. Germany was a defeated country in the First World War. She was forced to sign the Treaty of Versailles. She had to pay huge indemnity and give up territories. She was forbidden to station troops in a certain area in its own boundary. Germany wanted to take revenge and to restore the national glory. Second, there was the discontent of Italy. She joined the Allied Powers in the First World War because they promise to give her some land. Though she was a victorious power, was unhappy with the Treaty of Versailles as she failed to get what it wanted at the Paris Peace Conference.
Germany was the most responsible for the outbreak of the war. During the 1930s, Britain and France were trying hard o recover their economies. They had no time to check the aggression of the Axis Powers. Besides, they wanted to make use of Nazi Germany to check Communist USSR. They adopted an Appeasement policy In 1938, Germany threatened to take Sudetenland, a part of Czechoslovakia. Britain and France reached an agreement with Germany and gave Sudetenland to it because they hoped this could bring peace to Europe. But the appeasement policy only made Germany more aggressive. It soon occupied the whole of Czechoslovakia. Then it attacked Poland, and the Second World War began.
After the First World War, US played a leading role in the economic development of the world. She also lent money to Britain and France to help recover their economies, and to Germany to pay off its indemnity. As the American economy is prospering, Americans and industrialists issued shares on the stock market to raise money for further production. The stock prices increased