World War 2 is happening because Germany could not pay the damages of WW1 that they were supposed to pay. Aldolf Hitler became there leader. He wanted to get revenge on the country's. So he wanted to take control of them.
Aldolf Hitler leader of Germany
Aldolf Hitler became the dictator of Germany in 1933. He was mad that Germany had to pay for WW1. He hated Jews and blamed Jews for Germany's problems. He invaded a lot of people. He invaded Poland first.
Benito Mussolini Dictator of Italy
Benito Mussolini became the Dictator of Italy in 1922.The thing is that he took over his own country in 1936.
Francisco Franco became Dictator of Spain in 1939. He took over his own country and became the dictator.
He became the Dictator of the Soviet Union in 1924. Just like most everyone else he took over his own country.
Hideki Taio became prime minister of Japan in 1938. Joined the Axis powered. Took over his own country.
They didn't join the war because nobody attacked them. Also because they didn't want people die pointlessly.
On December 7, 1941 Japan attacked Pearl Habor, because of that the U.S joined the war.