World War II: Summary, Effects & Participants

Instructor: Nate Sullivan

Nate Sullivan holds a M.A. in History and a M.Ed. He is an adjunct history professor, middle school history teacher, and freelance writer.

In this lesson we will learn about World War II. We will examine the causes, leading figures involved, and the major themes and developments associated with mankind's most horrible conflict.

World War II: Mankind's Most Horrible Conflict

Hitler. Just about everyone knows this name. Adolf Hitler is one of the most, if not the most infamous name in history. As leader of Nazi Germany, Hitler was responsible for bringing about World War II, the most horrible conflict in human history. World War II raged between 1939-1945, and resulted in the deaths of between 60-80 million people. That number is unfathomable. The war brought destruction to the world on a scale never seen before, and not seen since. The war only came to an end with the dropping of the most destructive weapon in history: the atomic bomb. In this lesson we will look at World War II from a big picture approach. We learn about its central themes and developments. Let's go!

Causes of World War II

The causes of World War II are actually pretty simple, much more simple than the slew of complexities that led to the outbreak of World War I in 1914. World War II was basically one man's fault. Yep, you guessed it. Adolf Hitler. Adolf Hitler ascended to power throughout the 1920s and 1930s in the wake of Germany's devastating defeat in World War I. In 1933 he became the dictator of Nazi Germany, assuming the title of ''Fuhrer'', which means ''leader''. As Fuhrer of Germany, Hitler sought to restore Germany to a position of power. The official name of Hitler's party was the National Socialist German Workers' Party. The word ''Nazi'' itself is an abbreviation drawn from the party's name. Hitler and his Nazis were racists, believing the German (or Aryan) race was superior to all others, particularly to the Jewish race.

Adolf Hitler appearing on a German stamp.

During the mid to late 1930s, Hitler embarked on a program of aggression. He sought to expand German territory so as to create lebensraum or ''living space'' for the German people. To this end, he annexed or invaded other nations and regions piece by piece. In 1938 he annexed Austria in what is called the Anschluss. Soon after that he took over portions of Czechoslovakia. Meanwhile, the other European powers stood by idly, something historians have regarded as ''appeasement''. In 1939 Hitler's regime invaded Poland. At this point, Poland's allies, namely Great Britain and France decided enough was enough and came to Poland's defense, and thus the outbreak of World War II. So basically World War II began because of Hitler's military aggression.

Key Battles and Developments of the War

Nazi Germany was highly successful in the beginning stages of the conflict. After its successful invasion of Poland, the Wehrmacht (the German Army) turned west and invaded France. France fell within seven weeks. Now Hitler set his sights upon Great Britain. Originally he planned an amphibious invasion, but at this suggestion of his Luftwaffe (Air Force) chief, he decided to bomb the island nation into submission. During the Battle of Britain German and British planes fought for control over the skies over Great Britain between July and October 1940. The British were able to successfully defend their nation, despite suffering horrible destruction from German bombs.

All the while, the Soviet Union led by Joseph Stalin had been neutral in the war. It had even signed a non-aggression pact with Germany. However, Hitler betrayed its ally, and in June 1941 launched Operation Barbarossa, which was the code-name for the invasion of the Soviet Union. Soviet Russia was not fighting alongside France and Great Britain.

The United States was certainly alarmed at what was going on, but under the leadership of President Franklin D. Roosevelt, was determined to stay neutral. That changed when the Empire of Japan launched a surprise attack on Pearl Harbor, Hawaii on the morning of December 7, 1941. The United States and Japan were now participants. Great Britain, France, Soviet Russia, and the United States were called the Allied Powers, or the Allies; while Germany, Japan, and Italy were called the Axis Powers.

The surprise Japanese attack on Pearl Harbor is shown in this historic image.

The two major theaters of the war were the Pacific Theater and the European Theater. In the Pacific Theater, the American victory over the Japanese at the Battle of Midway in 1942 was a major turning point. Similarly, the Soviet victory over the Nazis at the Battle of Stalingrad between 1942-1943 was a turning point. The Battle of Stalingrad is often cited as the costliest battle in human history. After Stalingrad, the Nazis were on the defensive as the Soviet Red Army moved its way toward Germany. The Battle of Normandy, often known as D-Day, took place on June 6, 1944, and was the largest invasion force in history. The Allies were able to land successfully, allowing them a base to retake Nazi-occupied Europe.

Allied troops storm the beaches of Nazi occupied France during the Battle of Normandy.

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