! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 1939 -1945 Causes : Germany invading Great Britain Germany ↳France , Japans Poland " and France , allies attacking on " the Soviet September attack on , Germany against Germany ally ship , Italy Japan Germany on Union Great Britain and Soviet Union 's , 1st 1939 with Poland , declared war Pearl Harbor Axis power Outcome : - - - Atomic Bombing After the Red in Hiroshima Army knocked (Soviets ) Japan successfully of the war out invaded Berlin > Adolf Hitler killed himself 85 million deaths Impact on Great Britain : Bombardment destroyed many British Cities The economy in was disarray > Britain built up sterling credits (debts to other countries > After the War : Founding of the United Nations 500 million people in former colonies become Britain joins the EU Riots from Black Immigrants against bad independent housing in London , Liverpool and Bristol