What are the factors leading to World War II 1939-1945?

There
were many causes of. The most significant cause was the rise of Nazism in Germany. This itself
had causes reaching back to the end of World War I and the Treaty of Versailles, which, in
combination with the Great Depression, left the German people embittered and paved the way for
ultra-nationalist leader like Hitler. Another cause was the aggressive actions of the militarist
regime in Japan, whose invasion of China many...