World War II: Causes, Key Events & Impact

• World War II spanned from September 1, 1939, to May 7, 1945 (Europe) and September 2, 1945 (Pacific).
• The Allies and the Axis Powers engaged in the conflict.
• The war led to the decline of colonial empires and the rise of the United States and the Soviet Union as superpowers.
• The United Nations (UN) was created as a result of the war.

World War II Key Details

• Start date was September 1, 1939.
• End dates were May 7, 1945 (Europe) and September 2, 1945 (Pacific).
• Allied Powers included the United States, Soviet Union, United Kingdom, France, China, Canada, and Australia.
• Axis Powers included Germany, Italy, and Japan.
• Significant battles were the Battle of Stalingrad, Battle of Midway, D-Day, and Battle of the Bulge.
• Key treaties included the Treaty of Versailles (1919), Molotov-Ribbentrop Pact (1939), Yalta Conference (1945), and Potsdam Conference (1945).

Causes of World War II

• The Treaty of Versailles (1919) imposed harsh penalties on Germany after World War I, leading to political instability
• The rise of the Nazi Party under Hitler in Germany led to militarization and expansionist policies in the 1930s.
• Benito Mussolini's fascist regime in Italy sought to restore the Roman Empire
• Under Emperor Hirohito, Japan adopted militaristic expansion and invaded China in 1937

Expansionism and Aggression

• Germany rebuilt its military and annexed Austria (Anschluss, 1938) and Czechoslovakia (Sudetenland Crisis), violating the Treaty of Versailles.
• Japan invaded Manchuria in 1931 and launched a full-scale invasion of China in 1937.
• Italy invaded Ethiopia in 1935.

Failure of the League of Nations

• The League of Nations failed to take decisive action against Nazi Germany, Fascist Italy, and Imperial Japan
• Britain and France pursued appeasement, allowing Hitler's aggressions to go unchecked

The Nazi-Soviet Non-Aggression Pact (1939)

• Germany and the Soviet Union agreed to divide Poland.
• This emboldened Hitler to invade Poland on September 1, 1939, triggering the war

Invasion of Poland and the Beginning of the War (September 1939)

• Germany invaded Poland on September 1, 1939, using blitzkrieg tactics.
• Britain and France declared war on Germany on September 3, 1939.
• The Soviet Union invaded Poland from the east on September 17, 1939.

Fall of France and the Battle of Britain (1940)

• Germany quickly defeated Denmark, Norway, Belgium, and the Netherlands.
• France surrendered to Germany in June 1940.
• The Battle of Britain (July–October 1940) saw German Luftwaffe air raids over Britain.
• The British Royal Air Force (RAF) successfully repelled the attacks.

Operation Barbarossa: Germany Invades the Soviet Union (1941)

• Hitler launched Operation Barbarossa on June 22, 1941, invading the Soviet Union.
• The German Wehrmacht advanced deep into Soviet territory but was eventually halted at Stalingrad (1942–1943)

The Attack on Pearl Harbor and U.S. Entry (December 1941)

• Japan bombed Pearl Harbor on December 7, 1941, leading the United States to enter the war.
• The Pacific Theater saw intense battles between Japan and the U.S.

Turning Points (1942–1943)

• At The Battle of Midway (June 1942), the U.S. navy decisively defeated the Japanese fleet.
• The Soviets encircled and defeated German forces at the Battle of Stalingrad (1942–1943).
• Allied landings in North Africa (Operation Torch, 1942) pushed Axis forces out of Africa.

D-Day and the Liberation of Europe (1944–1945)

• On June 6, 1944 (D-Day), Allied forces landed in Normandy, France, beginning the liberation of Western Europe.
• By April 1945, the Allies had advanced into Germany.

The Fall of Berlin and German Surrender (May 1945)

• In April 1945, the Soviet Red Army captured Berlin.
• Adolf Hitler committed suicide on April 30, 1945.
• Germany surrendered on May 7, 1945.

The Pacific War and Japan's Surrender (August 1945)

• The U.S. dropped atomic bombs on Hiroshima (August 6, 1945) and Nagasaki (August 9, 1945).
• Japan surrendered on September 2, 1945, marking the end of World War II.

Consequences of World War II

• Over 70 million people died.
• Entire cities were destroyed, and economies collapsed.

Rise of the Superpowers

• The United States and the Soviet Union emerged as superpowers.
• The world became bipolar, leading to the Cold War.

The Establishment of the United Nations (UN)

• The United Nations (UN) was created in 1945 to prevent future conflicts.

The Cold War and Division of Germany

• Germany was divided into West Germany (democratic) and East Germany (communist).
• the Soviet Union controlled Eastern Europe, leading to the Cold War.

Decolonization

• European empires weakened, leading to the independence of India (1947), Indonesia (1949), and African nations.