|Previous: Spanish Civil War, Second Italo-Abyssinian War|
|Concurrent: Second Sino-Japanese War|
|Next: Chinese Civil War, Greek Civil War, Cold War|
|World War II|
|Date: 1 September 1939-2 September 1945|
|Outcome: Allied victory:|
World War II was a global war that lasted from 1 September 1939 to 2 September 1945, involving the vast majority of the world's nations and all of its great powers; over 30 nations took part in the war. The war was fought between the fascist Axis Powers (led by Nazi Germany, Italy, and Japan) and the democratic Allied Powers (led by the United Kingdom, United States, and Soviet Union), with alliances changing as new nations entered the war or switched sides. The war began after German dictator Adolf Hitler ordered the invasion of Poland, an ally of the United Kingdom and France, and Germany would ally with Italy and Japan to carve out large empires across the world.
In 1939-1940, the Axis took over almost all of Europe, with the Germans invading Poland, the Netherlands, Belgium, France, Denmark, and Norway. The Germans pressured weaker dictatorships such as Hungary, Romania, and Bulgaria to join the Axis in late 1940 and early 1941, while Japan took advantage of the battle of France to occupy French Indochina, a base from which it could continue its bloody war with China (which had started back in 1937).
In 1941, the war changed dramatically when Nazi Germany invaded the communist Soviet Union and Japan launched a surprise attack on the United States at Pearl Harbor, with the Germans hoping to destroy communism and the Japanese hoping to prevent the United States from assisting China during the Second Sino-Japanese War. Several nations joined the Allies, and the Allied Powers would fight to liberate occupied territories across the world from 1941 to 1945. The Germans were halted in their advance on the Soviet capital of Moscow in December 1941, the same month as the attack on Pearl Harbor. In 1942-43, the Allies would begin their counterattacks, liberating North Africa from Germany and Italy, knocking Italy out of the war following the invasion of Sicily in July-September 1943, pushing the Germans into the Ukraine and Belarus on the Russian front, and recapturing several occupied islands from the Japanese in the Pacific. In 1944, the Soviets and Allies both launched offensives against the Axis in Europe, with the Western Allies liberating France and much of Western Europe as the Soviets liberated much of Eastern Europe before halting in central Poland. In the Pacific, the Americans continued to capture more Japanese-occupied islands, and they liberated several islands in the Philippines. The final year of the war, 1945, saw the Soviets and Western Allies divide Germany in two after meeting along the Elbe River, while the Soviets and allied partisans liberated the Balkans. The Soviets conquered the German capital of Berlin on 2 May 1945, and Hitler killed himself; Mussolini was killed by partisans in Italy. On 8 May 1945, the war in Europe ended when Germany signed a document of unconditional surrender, and Germany was divided into occupation zones. In Asia, the war raged on, and the Americans seized the islands of Iwo Jima and Okinawa from the Japanese. In August, the Americans dropped two nuclear bombs on Japan, causing massive casualties and damage in the cities of Hiroshima and Nagasaki. Astonished at the sheer terror of biological warfare, as well as Japan's bombardment by constant firebombings, Emperor Hirohito announced the surrender of Japan on 15 August. On 2 September, Japan signed a formal surrender document in Tokyo Bay, ending the war.
Anywhere from 50,000,000 to 80,000,000+ people died as a result of World War II, the bloodiest war in history. Many of them were civilians, including the 10,000,000 victims of Nazi war crimes such as the Holocaust (the genocide against Jews and the massacre of intellectuals, gypsies, homosexuals, handicapped people, Slavs, and Red Army prisoners-of-war) and the massacres carried out against civilians in occupied areas. The USSR lost 26,600,000 people in the war, including both soldiers and civilians from causes such as war, famine, or genocide. 25,000,000 soldiers perished in the war, including 5,000,000 in prisoner-of-war camps.
World War II had a vast array of effects on world history, and it has been universally considered to be a turning point in world history. Several borders were changed, with Japan, Italy, and Germany losing their conquests during the war, Poland gaining more land along the Oder River while losing some in the east, and several colonies gaining independence from the great British, French, Italian, Dutch and other empires in the years following the war. It would take years for Europe to be rebuilt under the Marshall Plan, but the war-torn countries would enjoy an economic boom after the war. In America, a "baby boom" occurred as the economy soared due to war production and the return of males to the workforce from overseas service. Devastated countries such as Germany and Japan also rebuilt their economies. However, the end of World War II would bring more issues, as the Soviets refused to leave Eastern Europe, setting up communist puppet governments and garrisoning them with troops. The Western Allies and Soviets divided Europe along the "Iron Curtain" from Szeczin in the Baltics to Trieste in Yugoslavia, with Germany being divided between the capitalist West Germany and the communist East Germany. With fascism defeated, the Cold War would see a clash of ideals between communism and democracy, although there was no direct warfare between the two sides; instead, the Cold War consisted of proxy wars such as the Korean War and Vietnam War. The war forever changed the world, and its effects are still felt in nearly every country, as World War II caused most of the demographic, political, social, economic, and military changes felt after the 1940s.