World War II

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    <div style="font-size: 1.2em;">{{Colorlink|World War II|#fff}}</div>
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    ! colspan="4" style="background-color: #536349; color: #fff;" | '''Overview'''
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    ! style="background-color: #536349; color: #fff; width: 100px;" | Course
    | colspan="3" style="text-align: left;" | [[Causes of World War II|Causes]] · [[World War II timeline|Timeline]] · [[Theaters of World War II|Theaters of war]]
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    ! style="background-color: #536349; color: #fff;" | Participants
    | colspan="3" style="text-align: left;" | [[Allies of World War II|Allies]] · [[Axis powers]]
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    ! style="background-color: #536349; color: #fff;" | Casualties
    | colspan="3" style="text-align: left;" | [[World War II casualties|Casualties]] · [[The Holocaust]] · [[War crimes in World War II|War crimes]]
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    ! colspan="4" style="background-color: #536349; color: #fff;" | '''{{Colorlink|European theater of World War II|#fff|European Theater}}'''
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    ! style="background-color: #536349; color: #fff; width: 100px;" | 1939–1940
    | colspan="3" style="text-align: left;" | [[Invasion of Poland]] · [[Winter War]] · [[Phoney War]] · [[Invasion of Denmark and Norway|Invasion of Norway and Denmark]] · [[Battle of France]] · [[Dunkirk evacuation]] · [[Battle of Britain]] · [[The Blitz]]
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    ! style="background-color: #536349; color: #fff;" | 1941–1942
    | colspan="3" style="text-align: left;" | [[Balkans campaign (World War II)|Balkans campaign]] · [[Operation Barbarossa]] · [[Siege of Leningrad]] · [[Battle of Moscow]] · [[Battle of Stalingrad]]
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    ! style="background-color: #536349; color: #fff;" | 1943–1945
    | colspan="3" style="text-align: left;" | [[Battle of Kursk]] · [[Allied invasion of Sicily]] · [[Allied invasion of Italy]] · [[D-Day|D-Day (Normandy landings)]] · [[Operation Bagration]] · [[Battle of the Bulge]] · [[Battle of Berlin]] · [[Victory in Europe Day|V-E Day]]
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    ! colspan="4" style="background-color: #536349; color: #fff;" | '''{{Colorlink|Pacific War|#fff|Pacific Theater}}'''
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    ! style="background-color: #536349; color: #fff; width: 100px;" | 1937–1942
    | colspan="3" style="text-align: left;" | [[Second Sino-Japanese War]] · [[Attack on Pearl Harbor]] · [[Battle of Wake Island|Wake Island]] · [[Fall of Singapore]] · [[Battle of the Coral Sea|Coral Sea]] · [[Battle of Midway]]
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    ! style="background-color: #536349; color: #fff;" | 1942–1945
    | colspan="3" style="text-align: left;" | [[Guadalcanal Campaign|Guadalcanal]] · [[Burma campaign]] · [[Battle of the Philippine Sea|Philippine Sea]] · [[Battle of Leyte Gulf|Leyte Gulf]] · [[Battle of Iwo Jima|Iwo Jima]] · [[Battle of Okinawa|Okinawa]] · [[Atomic bombings of Hiroshima and Nagasaki|Atomic bombings]] · [[Surrender of Japan]]
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    ! colspan="4" style="background-color: #536349; color: #fff;" | '''{{Colorlink|North African campaign|#fff|Other Theaters}}'''
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    ! style="background-color: #536349; color: #fff; width: 100px;" | Africa & Med.
    | colspan="3" style="text-align: left;" | [[North African campaign]] · [[Second Battle of El Alamein|El Alamein]] · [[Operation Torch]] · [[Battle of the Atlantic]] · [[Mediterranean theater of World War II|Mediterranean]]
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    ! colspan="4" style="background-color: #536349; color: #fff;" | '''Key Figures'''
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    ! style="background-color: #536349; color: #fff; width: 100px;" | Allied leaders
    | colspan="3" style="text-align: left;" | [[Franklin D. Roosevelt]] · [[Harry S. Truman]] · [[Winston Churchill]] · [[Joseph Stalin]] · [[Charles de Gaulle]] · [[Chiang Kai-shek]]
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    ! style="background-color: #536349; color: #fff;" | Axis leaders
    | colspan="3" style="text-align: left;" | [[Adolf Hitler]] · [[Benito Mussolini]] · [[Hideki Tojo]] · [[Emperor Hirohito]]
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    ! style="background-color: #536349; color: #fff;" | Commanders
    | colspan="3" style="text-align: left;" | [[Dwight D. Eisenhower]] · [[Douglas MacArthur]] · [[George S. Patton]] · [[Bernard Montgomery]] · [[Georgy Zhukov]] · [[Erwin Rommel]] · [[Isoroku Yamamoto]]
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    ! colspan="4" style="background-color: #536349; color: #fff;" | '''Aftermath'''
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    ! style="background-color: #536349; color: #fff; width: 100px;" | Postwar
    | colspan="3" style="text-align: left;" | [[Aftermath of World War II]] · [[United Nations]] · [[Nuremberg Trials]] · [[International Military Tribunal for the Far East|Tokyo Trials]] · [[Cold War]] · [[Marshall Plan]] · [[Decolonization]] · [[Division of Germany]] · [[Occupation of Japan]]
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{| style="width: 450px; border: 2px solid #536349;"
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! colspan="2" style="background-color: #536349; color: #fff; font-size: 1.2em;" | World War II
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! colspan="2" style="padding: 0;"| ![[Second_world_war_europe_animation.gif]] <div style="font-size: 0.85em;">European theatre of World War II animation map, 1939–1945 – Red: Western Allies and the Soviet Union after 1941; Green: Soviet Union before 1941; Blue: Axis powers</div>
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! colspan="2" style="background-color: #536349; color: #fff;" | Overview
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! style="background-color: #eef2eb; width: 30%;" darkstyle="background-color: var(--wiki-surface);" | Date
| September 1, 1939 – September 2, 1945<br><small>(6 years and 1 day)</small>
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! style="background-color: #eef2eb;" darkstyle="background-color: var(--wiki-surface);" | Location
| [[List of theaters and campaigns of World War II|Global]]
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! style="background-color: #eef2eb;" darkstyle="background-color: var(--wiki-surface);" | Result
| [[Allies of World War II|Allied]] victory
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! colspan="2" style="background-color: #536349; color: #fff;" | [[World War II by country|Participants]]
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! style="background-color: #eef2eb;" darkstyle="background-color: var(--wiki-surface);" | {{Colorlink|Allies of World War II|color-mix(in srgb, #536349 55%, #f5f5f7)|Allies}}
| {{Colorlink|Axis powers|color-mix(in srgb, #536349 55%, #f5f5f7)|Axis}}
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! colspan="2" style="background-color: #536349; color: #fff;" | Commanders
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'''[[Allied leaders of World War II|Allied leaders]]:'''<br>
[[Joseph Stalin]]<br>
[[Franklin D. Roosevelt]]<br>
[[Winston Churchill]]<br>
[[Chiang Kai-shek]]
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'''[[Axis leaders of World War II|Axis leaders]]:'''<br>
[[Adolf Hitler]]<br>
[[Hirohito]]<br>
[[Benito Mussolini]]
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! colspan="2" style="background-color: #536349; color: #fff;" | Casualties
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| colspan="2" style="text-align: center;" | 60 million to over 75 million deaths<br><small>(military and civilian combined)</small>
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World War II (also called the Second World War) was a global conflict fought from September 1, 1939, to September 2, 1945. It pitted two major alliances against each other: the [[Allies of World War II|Allies]] (led by the [[United Kingdom]], the [[Soviet Union]], the [[United States]], and [[China]]) and the [[Axis powers]] (led by [[Nazi Germany]], [[Fascist Italy]], and the [[Empire of Japan]]). Nearly every country in the world was involved in some way, and many nations committed all of their resources in pursuit of [[total war]].

World War II is the deadliest conflict in human history. Between 70 and 85 million people died, more than half of them civilians. Millions were killed in [[genocide]]s, including [[the Holocaust]], in which Nazi Germany systematically murdered around six million [[Jews]] along with millions of others. The war also saw the first and only use of [[nuclear weapons]] in combat, when the United States dropped [[atomic bombs]] on the Japanese cities of [[Hiroshima]] and [[Nagasaki]] in August 1945.

The war's causes stretched back to the aftermath of [[World War I]]. The harsh terms of the [[Treaty of Versailles]] left Germany bitter and economically struggling. The rise of [[fascism]] in Europe and [[militarism]] in Japan pushed the world toward another conflict. Key events leading up to the war included Japan's [[invasion of Manchuria]] in 1931, the [[Spanish Civil War]] (1936–1939), the [[Second Sino-Japanese War]] starting in 1937, and Germany's annexation of [[Austria]] and the [[Sudetenland]] in 1938.

After the Allied victory, the [[United Nations]] was created to promote international cooperation and prevent future wars. The [[Soviet Union]] and the [[United States]] emerged as rival [[superpowers]], setting the stage for the decades-long [[Cold War]]. European colonial empires weakened, triggering [[decolonization]] across Africa and Asia. The war fundamentally reshaped the political, economic, and social structures of the entire world.

= Background and causes =

== The aftermath of World War I ==

[[World War I]] (1914–1918) had dramatically reshaped Europe. The defeated [[Central Powers]] — including [[Germany]], [[Austria-Hungary]], [[Bulgaria]], and the [[Ottoman Empire]] — lost territory and influence. New nations like [[Poland]], [[Czechoslovakia]], and [[Yugoslavia]] were carved out of the old empires. The [[Russian Empire]] collapsed into revolution and became the [[Soviet Union]].

To prevent another world war, the [[League of Nations]] was established in 1920 through the [[Paris Peace Conference]]. Its goals were to settle disputes through negotiation and to promote disarmament. However, the League lacked enforcement power and would prove unable to stop aggression in the 1930s.

== The Treaty of Versailles and the rise of fascism ==

The [[Treaty of Versailles]] (1919) punished Germany severely. Germany lost about 13 percent of its European territory and all of its overseas colonies. It was forced to pay heavy [[reparations]] (financial penalties) to the Allies and had strict limits placed on the size of its military. These terms created deep resentment among many Germans.

During the [[Great Depression]] of the 1930s, economic hardship and political instability pushed people toward extreme political movements. In Germany, [[Adolf Hitler]] and the [[Nazi Party]] rose to power, promising to undo the Versailles Treaty and restore German greatness. Hitler became chancellor in 1933 and quickly established a [[totalitarian]] state (a government with total control over public and private life). He promoted a racist ideology centered on the supposed superiority of an "Aryan" race, and he targeted [[Jews]], [[Slavic peoples]], and other groups as enemies.

In Italy, the [[fascism|fascist]] movement under [[Benito Mussolini]] had already seized power in the 1920s. Mussolini promised to make Italy a great power and pursued aggressive expansion, including the [[Second Italo-Ethiopian War|invasion of Ethiopia]] in 1935.

In Japan, the military gained increasing control over the government during the 1930s. Japan sought to dominate East Asia and began expanding aggressively, starting with the [[invasion of Manchuria]] in 1931, where it set up the puppet state of [[Manchukuo]].

== Steps toward war ==

Throughout the mid-1930s, the aggressive moves by Germany, Italy, and Japan met with weak responses from other major powers — a policy known as [[appeasement]]. When Germany remilitarized the [[Rhineland]] in 1936, breaking the Versailles Treaty, Britain and France did nothing. When Italy invaded Ethiopia, the League of Nations imposed limited sanctions that had little effect.

Hitler and Mussolini supported the [[Nationalist faction (Spanish Civil War)|Nationalist rebels]] in the [[Spanish Civil War]] (1936–1939), using it as a testing ground for their weapons and tactics. The [[Soviet Union]] supported the opposing Republican government. The Nationalists won, and Spain under dictator [[Francisco Franco]] remained officially neutral during World War II but generally favored the Axis.

In July 1937, Japan launched a full-scale [[Second Sino-Japanese War|invasion of China]], capturing major cities including Beijing, Shanghai, and the capital Nanjing. After the fall of Nanjing, Japanese forces committed the [[Nanjing Massacre]], killing tens or hundreds of thousands of Chinese civilians.

In March 1938, Germany annexed [[Austria]] (the [[Anschluss]]) with almost no resistance. Then, at the [[Munich Agreement]] in September 1938, Britain and France agreed to let Germany take the [[Sudetenland]] (the German-speaking part of Czechoslovakia) in exchange for Hitler's promise that he would seek no more territory. British Prime Minister [[Neville Chamberlain]] famously declared this would bring "peace for our time." It did not. In March 1939, Germany seized the rest of Czechoslovakia.

Alarmed at last, Britain and France pledged to defend [[Poland]] if it were attacked. On August 23, 1939, Germany and the Soviet Union stunned the world by signing the [[Molotov–Ribbentrop Pact]], a non-aggression agreement. Secretly, the pact divided Eastern Europe into German and Soviet "spheres of influence" (areas each power would control).

= The war in Europe (1939–1941) =

== The invasion of Poland and the Phoney War ==

On September 1, 1939, Germany [[Invasion of Poland|invaded Poland]], using a new tactic called [[blitzkrieg]] ("lightning war") — fast-moving coordinated attacks using tanks, infantry, and air power. Britain and France declared war on Germany on September 3, but they provided little direct military help to Poland.

On September 17, the Soviet Union invaded Poland from the east, as secretly agreed in the Molotov–Ribbentrop Pact. Poland was divided between Germany and the Soviet Union by the end of the month. Despite its military defeat, Poland never formally surrendered. A [[Polish government-in-exile]] was formed, and many Polish soldiers escaped to continue fighting with the Allies.

What followed in Western Europe was the so-called "[[Phoney War]]" — months of declared war with almost no actual fighting between Germany and the Western Allies. During this time, the Soviet Union invaded [[Finland]] in November 1939 (the [[Winter War]]), and the Soviets forced the [[Baltic states]] (Estonia, Latvia, Lithuania) to accept Soviet military bases.

== The fall of Western Europe ==

In April 1940, Germany invaded [[Denmark]] and [[Norway]] to secure supply routes for Swedish iron ore. Then, on May 10, 1940, Germany launched its massive assault westward, invading [[Belgium]], the [[Netherlands]], [[Luxembourg]], and [[France]]. Using blitzkrieg tactics and a surprise attack through the [[Ardennes]] forest (which the French thought was impassable for tanks), Germany bypassed France's heavily fortified [[Maginot Line]].

The British Expeditionary Force and portions of the French army were pushed to the coast at [[Dunkirk evacuation|Dunkirk]], where over 300,000 Allied soldiers were evacuated across the English Channel in a dramatic rescue operation. France fell in June 1940, and was divided into German-occupied zones and the collaborationist [[Vichy France]] government in the south.

Italy declared war on France and Britain on June 10, 1940, hoping to gain territory from France's collapse.

== Britain stands alone ==

With France defeated, Britain stood virtually alone against Germany. Hitler planned an invasion of Britain ([[Operation Sea Lion]]), but first needed to gain control of the skies. The [[Battle of Britain]] (July–October 1940) was a fierce air campaign between the German [[Luftwaffe]] and the British [[Royal Air Force]] (RAF). The RAF successfully defended British airspace, and Hitler called off the invasion plans.

Germany then shifted to nighttime bombing raids on British cities, known as [[the Blitz]], killing tens of thousands of civilians. Meanwhile, the [[Battle of the Atlantic]] raged at sea, as German [[U-boat]]s (submarines) tried to cut off Britain's supply lines by sinking merchant ships.

== The Mediterranean and the Balkans ==

In September 1940, Italy invaded British-held [[Egypt]] from its colony in [[Libya]], starting the [[North African campaign]]. Italy also invaded [[Greece]] in October 1940 but was pushed back into [[Albania]]. Germany intervened in early 1941, conquering [[Yugoslavia]], [[Greece]], and the island of [[Crete]] by May. In North Africa, German General [[Erwin Rommel]] (nicknamed "the Desert Fox") led combined German-Italian forces that pushed the British back toward Egypt.

= The war expands (1941) =

== Operation Barbarossa ==

On June 22, 1941, Germany launched [[Operation Barbarossa]], the invasion of the Soviet Union. It was the largest land invasion in history, involving over three million German and Axis soldiers. The attack opened the massive [[Eastern Front (World War II)|Eastern Front]], which would become the deadliest theater of the entire war.

The Axis forces made rapid gains during the summer, capturing vast stretches of [[Ukraine]] and the [[Baltic states]] and inflicting enormous casualties on the [[Red Army]]. However, as winter set in, the German advance stalled just outside [[Moscow]]. The Soviets launched a counterattack in December 1941, pushing the Germans back. The failure to capture Moscow marked the end of Germany's blitzkrieg strategy — the war in the east would become a long, grinding struggle.

== Pearl Harbor and America enters the war ==

Meanwhile, tensions had been rising between Japan and the Western powers. Japan's occupation of [[French Indochina]] led the United States, Britain, and the Netherlands to impose an [[oil embargo]] (a ban on selling oil to Japan), which threatened Japan's ability to fuel its military.

On December 7, 1941, Japan [[Attack on Pearl Harbor|attacked the American naval base at Pearl Harbor]] in [[Hawaii]], destroying much of the U.S. Pacific Fleet. Simultaneously, Japan attacked British and American territories across Southeast Asia and the Pacific, including the [[Philippines]], [[Malaya]], [[Hong Kong]], and [[Wake Island]].

The United States declared war on Japan on December 8, and Germany and Italy declared war on the United States on December 11. America's entry transformed the war into a truly global conflict. The U.S. and Britain agreed on a "Europe First" strategy — defeating Germany would be the top priority, while fighting a holding action against Japan.

By mid-1942, Japan had conquered a vast empire stretching from [[Burma]] to the [[Dutch East Indies]] to the western Pacific islands.

= The tide turns (1942–1943) =

== Key battles ==

Three major turning points shifted the war in the Allies' favor:

'''The Battle of Midway (June 1942):''' In the Pacific, the U.S. Navy ambushed a Japanese fleet near [[Midway Island]], sinking four Japanese aircraft carriers. This decisive victory halted Japan's naval expansion and gave the U.S. the initiative in the Pacific.

'''The Battle of Stalingrad (August 1942 – February 1943):''' On the Eastern Front, Germany pushed deep into southern Russia, aiming to capture the oil fields of the [[Caucasus]]. The German Sixth Army became locked in brutal street-by-street fighting in the city of [[Stalingrad]] (now Volgograd). In November 1942, the Soviets launched a massive counterattack that encircled the German forces. After months of starvation and combat, the remaining German troops surrendered in February 1943. Stalingrad was one of the bloodiest battles in history and is widely considered the turning point of the war in Europe.

'''El Alamein and North Africa (October 1942 – May 1943):''' In [[Egypt]], British forces under General [[Bernard Montgomery]] defeated Rommel's Afrika Korps at the [[Second Battle of El Alamein]] in October–November 1942. Combined with the Anglo-American landings in French North Africa ([[Operation Torch]]) in November 1942, this led to the complete Axis defeat in North Africa by May 1943.

== The invasion of Italy ==

With North Africa secured, the Allies [[Allied invasion of Sicily|invaded Sicily]] in July 1943. The invasion triggered the overthrow of Mussolini, and Italy signed an [[armistice]] (ceasefire agreement) with the Allies in September 1943. However, Germany quickly occupied most of Italy, rescued Mussolini, and set up a puppet state in the north called the [[Italian Social Republic]]. The Allies fought their way slowly up the Italian peninsula against strong German defenses.

== The Eastern Front turns ==

After Stalingrad, the initiative on the Eastern Front shifted permanently to the Soviet Union. In July 1943, Germany attempted one last major offensive at the [[Battle of Kursk]], the largest tank battle in history. The well-prepared Soviet defenses held, and the counterattack that followed began a relentless Soviet advance westward that would continue until the war's end.

= Allied victory (1944–1945) =

== D-Day and the liberation of France ==

On June 6, 1944 — known as [[D-Day]] — the Allies launched [[Operation Overlord]], the largest amphibious (sea-to-land) invasion in history. Over 150,000 Allied soldiers landed on the beaches of [[Normandy]], France. Despite heavy casualties, the invasion succeeded, and the Allies established a foothold in Western Europe.

Paris was liberated in August 1944, and Allied forces pushed eastward toward Germany. In December 1944, Germany launched a last-ditch counteroffensive in the [[Ardennes]] forest in Belgium, known as the [[Battle of the Bulge]]. It was the largest battle the U.S. Army fought in the war, but after initial German success, the Allies pushed them back.

== The Soviet advance ==

On the Eastern Front, the Soviets launched a massive summer offensive in June 1944 called [[Operation Bagration]], which destroyed the German Army Group Center and liberated [[Belarus]]. By early 1945, Soviet forces had pushed into Poland, Romania, Bulgaria, Hungary, and were closing in on Germany itself.

== The fall of Germany ==

By spring 1945, Allied forces were closing in from both east and west. The Western Allies crossed the [[Rhine River]] in March 1945. The Soviets launched their final assault on [[Battle of Berlin|Berlin]] in April. On April 30, 1945, with Soviet troops just blocks from his underground bunker, [[Adolf Hitler]] committed suicide. Germany surrendered unconditionally on May 7–8, 1945, a date celebrated as [[Victory in Europe Day|V-E Day]] (Victory in Europe Day).

== The war in the Pacific ==

While the war in Europe raged, the Allies had been steadily pushing back Japan in the Pacific using an "[[island hopping]]" strategy — capturing key islands and bypassing others to get closer to Japan.

Major Pacific battles included [[Guadalcanal Campaign|Guadalcanal]] (1942–1943), the [[Philippines|reconquest of the Philippines]] (1944–1945), [[Battle of Iwo Jima|Iwo Jima]] (February–March 1945), and [[Battle of Okinawa|Okinawa]] (April–June 1945). Japanese resistance was fierce, with many soldiers fighting to the death and [[kamikaze]] pilots deliberately crashing their planes into Allied ships.

By mid-1945, massive Allied bombing raids had devastated Japanese cities, and a naval blockade had cut off Japan's imports. Still, Japan refused to surrender unconditionally.

== Atomic bombs and Japan's surrender ==

On August 6, 1945, the United States dropped an atomic bomb called "[[Little Boy]]" on [[Hiroshima]], killing an estimated 80,000 people instantly (with tens of thousands more dying later from radiation). On August 9, a second bomb called "[[Fat Man]]" was dropped on [[Nagasaki]], killing around 40,000 people instantly.

On August 8, the Soviet Union declared war on Japan and invaded Japanese-held [[Manchuria]], quickly defeating the Japanese forces there.

Faced with the atomic bombs, the Soviet invasion, and the prospect of further destruction, [[Emperor Hirohito]] of Japan announced the country's surrender on August 15, 1945 ([[Victory over Japan Day|V-J Day]]). The formal surrender documents were signed on September 2, 1945, aboard the [[USS Missouri]] in [[Tokyo Bay]], officially ending World War II.

= The Holocaust and war crimes =

== The Holocaust ==

[[The Holocaust]] was the systematic, state-sponsored murder of approximately six million Jews by Nazi Germany and its collaborators. The Nazis also targeted [[Roma people]], [[Slavic peoples]], disabled people, [[homosexuality|homosexuals]], political opponents, and others — bringing the total number of victims to 11 to 17 million.

The killing was carried out through mass shootings, forced labor, starvation, and [[extermination camps]] such as [[Auschwitz]], [[Treblinka]], and [[Sobibor]], where victims were murdered in gas chambers on an industrial scale.

== Other war crimes ==

Japan committed widespread atrocities in occupied territories, including the [[Nanjing Massacre]], the use of [[comfort women]] (forced sex slaves), brutal treatment of [[prisoner of war|prisoners of war]], and medical experiments on prisoners (notably at [[Unit 731]]).

The Soviet Union also committed atrocities, including the [[Katyn massacre]] (the killing of thousands of Polish officers) and mass deportations of ethnic groups.

After the war, German leaders were tried for war crimes at the [[Nuremberg Trials]], and Japanese leaders faced the [[International Military Tribunal for the Far East]] in Tokyo.

= Aftermath and legacy =

== Political changes ==

World War II fundamentally reshaped the world order. The [[United Nations]] was established on October 24, 1945, to promote international cooperation and prevent future wars. The five major Allied powers — the United States, the Soviet Union, the United Kingdom, France, and China — became the permanent members of the [[United Nations Security Council|UN Security Council]], each with [[veto]] power.

Germany was divided into four occupation zones controlled by the U.S., Britain, France, and the Soviet Union. This division eventually led to the creation of two separate countries: [[West Germany]] (aligned with the Western democracies) and [[East Germany]] (a Soviet-backed communist state). They would not reunify until 1990.

Japan was occupied by American forces under General [[Douglas MacArthur]]. A new democratic constitution was adopted, and Japan renounced war as a means of settling international disputes.

== The Cold War ==

The wartime alliance between the Western powers and the Soviet Union quickly broke down. The United States and the Soviet Union emerged as rival [[superpowers]] with opposing ideologies — [[capitalism]] and [[democracy]] versus [[communism]]. This rivalry, known as the [[Cold War]], dominated global politics for nearly half a century (1947–1991) and led to the formation of the U.S.-led [[NATO]] and the Soviet-led [[Warsaw Pact]].

== Decolonization ==

The war weakened European colonial powers, accelerating the process of [[decolonization]]. In the decades following the war, dozens of countries in Africa, Asia, and the Middle East gained independence from European rule. In some cases this happened peacefully; in others, like in [[Algeria]] and [[Vietnam]], it involved bitter wars of independence.

== Economic recovery ==

The United States, which emerged from the war with its homeland largely undamaged, became the world's dominant economic power. Through the [[Marshall Plan]] (1948–1952), the U.S. provided about $13 billion (around $170 billion in today's dollars) to help rebuild Western Europe. Japan and West Germany also experienced remarkable economic recoveries in the postwar decades.

= Key figures =

The war involved many influential leaders on both sides:

'''Allied leaders:''' [[Franklin D. Roosevelt]] and later [[Harry S. Truman]] (United States), [[Winston Churchill]] (United Kingdom), [[Joseph Stalin]] (Soviet Union), [[Charles de Gaulle]] (Free France), [[Chiang Kai-shek]] (China)

'''Axis leaders:''' [[Adolf Hitler]] (Nazi Germany), [[Benito Mussolini]] (Fascist Italy), [[Hideki Tojo]] and [[Emperor Hirohito]] (Japan)

'''Military commanders:''' [[Dwight D. Eisenhower]], [[Douglas MacArthur]], [[George S. Patton]] (U.S.); [[Bernard Montgomery]] (UK); [[Georgy Zhukov]] (Soviet Union); [[Erwin Rommel]] (Germany); [[Isoroku Yamamoto]] (Japan)

= By the numbers =

The scale of World War II was unprecedented:

'''Deaths:''' 70–85 million total (including about 50 million civilians)

'''Duration:''' 6 years (1939–1945 in Europe; related fighting in Asia from 1937)

'''Countries involved:''' Over 30 nations formally at war; nearly every country affected

'''Cost:''' The U.S. alone spent an estimated $296 billion (1945 dollars) — about $4.9 trillion in today's money

'''The Soviet Union''' suffered the most casualties of any nation, losing approximately 27 million people — roughly one in seven of its entire population.

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{|style="width: 100%; border: 2px solid #536349;" |- !style="background-color: #536349; padding: 10px;"| <div style="font-size: 1.2em;">{{Colorlink|World War II|#fff}}</div> |- |style="background-color: #fff;" darkstyle="background-color: var(--wiki-surface);"| {{Collapse|style="background-color: var(--wiki-bg);" darkstyle="background-color: var(--wiki-surface);"|color="#536349"}} ! colspan="4" style="background-color: #536349; color: #fff;" | '''Overview''' |- ! style="background-color: #536349; color: #fff; width: 100px;" | Course | colspan="3" style="text-align: left;" | [[Causes of World War II|Causes]] · [[World War II timeline|Timeline]] · [[Theaters of World War II|Theaters of war]] |- ! style="background-color: #536349; color: #fff;" | Participants | colspan="3" style="text-align: left;" | [[Allies of World War II|Allies]] · [[Axis powers]] |- ! style="background-color: #536349; color: #fff;" | Casualties | colspan="3" style="text-align: left;" | [[World War II casualties|Casualties]] · [[The Holocaust]] · [[War crimes in World War II|War crimes]] |- ! colspan="4" style="background-color: #536349; color: #fff;" | '''{{Colorlink|European theater of World War II|#fff|European Theater}}''' |- ! style="background-color: #536349; color: #fff; width: 100px;" | 1939–1940 | colspan="3" style="text-align: left;" | [[Invasion of Poland]] · [[Winter War]] · [[Phoney War]] · [[Invasion of Denmark and Norway|Invasion of Norway and Denmark]] · [[Battle of France]] · [[Dunkirk evacuation]] · [[Battle of Britain]] · [[The Blitz]] |- ! style="background-color: #536349; color: #fff;" | 1941–1942 | colspan="3" style="text-align: left;" | [[Balkans campaign (World War II)|Balkans campaign]] · [[Operation Barbarossa]] · [[Siege of Leningrad]] · [[Battle of Moscow]] · [[Battle of Stalingrad]] |- ! style="background-color: #536349; color: #fff;" | 1943–1945 | colspan="3" style="text-align: left;" | [[Battle of Kursk]] · [[Allied invasion of Sicily]] · [[Allied invasion of Italy]] · [[D-Day|D-Day (Normandy landings)]] · [[Operation Bagration]] · [[Battle of the Bulge]] · [[Battle of Berlin]] · [[Victory in Europe Day|V-E Day]] |- ! colspan="4" style="background-color: #536349; color: #fff;" | '''{{Colorlink|Pacific War|#fff|Pacific Theater}}''' |- ! style="background-color: #536349; color: #fff; width: 100px;" | 1937–1942 | colspan="3" style="text-align: left;" | [[Second Sino-Japanese War]] · [[Attack on Pearl Harbor]] · [[Battle of Wake Island|Wake Island]] · [[Fall of Singapore]] · [[Battle of the Coral Sea|Coral Sea]] · [[Battle of Midway]] |- ! style="background-color: #536349; color: #fff;" | 1942–1945 | colspan="3" style="text-align: left;" | [[Guadalcanal Campaign|Guadalcanal]] · [[Burma campaign]] · [[Battle of the Philippine Sea|Philippine Sea]] · [[Battle of Leyte Gulf|Leyte Gulf]] · [[Battle of Iwo Jima|Iwo Jima]] · [[Battle of Okinawa|Okinawa]] · [[Atomic bombings of Hiroshima and Nagasaki|Atomic bombings]] · [[Surrender of Japan]] |- ! colspan="4" style="background-color: #536349; color: #fff;" | '''{{Colorlink|North African campaign|#fff|Other Theaters}}''' |- ! style="background-color: #536349; color: #fff; width: 100px;" | Africa & Med. | colspan="3" style="text-align: left;" | [[North African campaign]] · [[Second Battle of El Alamein|El Alamein]] · [[Operation Torch]] · [[Battle of the Atlantic]] · [[Mediterranean theater of World War II|Mediterranean]] |- ! colspan="4" style="background-color: #536349; color: #fff;" | '''Key Figures''' |- ! style="background-color: #536349; color: #fff; width: 100px;" | Allied leaders | colspan="3" style="text-align: left;" | [[Franklin D. Roosevelt]] · [[Harry S. Truman]] · [[Winston Churchill]] · [[Joseph Stalin]] · [[Charles de Gaulle]] · [[Chiang Kai-shek]] |- ! style="background-color: #536349; color: #fff;" | Axis leaders | colspan="3" style="text-align: left;" | [[Adolf Hitler]] · [[Benito Mussolini]] · [[Hideki Tojo]] · [[Emperor Hirohito]] |- ! style="background-color: #536349; color: #fff;" | Commanders | colspan="3" style="text-align: left;" | [[Dwight D. Eisenhower]] · [[Douglas MacArthur]] · [[George S. Patton]] · [[Bernard Montgomery]] · [[Georgy Zhukov]] · [[Erwin Rommel]] · [[Isoroku Yamamoto]] |- ! colspan="4" style="background-color: #536349; color: #fff;" | '''Aftermath''' |- ! style="background-color: #536349; color: #fff; width: 100px;" | Postwar | colspan="3" style="text-align: left;" | [[Aftermath of World War II]] · [[United Nations]] · [[Nuremberg Trials]] · [[International Military Tribunal for the Far East|Tokyo Trials]] · [[Cold War]] · [[Marshall Plan]] · [[Decolonization]] · [[Division of Germany]] · [[Occupation of Japan]] {{Endcollapse}} |} {| style="width: 450px; border: 2px solid #536349;" |- ! colspan="2" style="background-color: #536349; color: #fff; font-size: 1.2em;" | World War II |- ! colspan="2" style="padding: 0;"| ![[Second_world_war_europe_animation.gif]] <div style="font-size: 0.85em;">European theatre of World War II animation map, 1939–1945 – Red: Western Allies and the Soviet Union after 1941; Green: Soviet Union before 1941; Blue: Axis powers</div> |- ! colspan="2" style="background-color: #536349; color: #fff;" | Overview |- ! style="background-color: #eef2eb; width: 30%;" darkstyle="background-color: var(--wiki-surface);" | Date | September 1, 1939 – September 2, 1945<br><small>(6 years and 1 day)</small> |- ! style="background-color: #eef2eb;" darkstyle="background-color: var(--wiki-surface);" | Location | [[List of theaters and campaigns of World War II|Global]] |- ! style="background-color: #eef2eb;" darkstyle="background-color: var(--wiki-surface);" | Result | [[Allies of World War II|Allied]] victory |- ! colspan="2" style="background-color: #536349; color: #fff;" | [[World War II by country|Participants]] |- ! style="background-color: #eef2eb;" darkstyle="background-color: var(--wiki-surface);" | {{Colorlink|Allies of World War II|color-mix(in srgb, #536349 55%, #f5f5f7)|Allies}} | {{Colorlink|Axis powers|color-mix(in srgb, #536349 55%, #f5f5f7)|Axis}} |- ! colspan="2" style="background-color: #536349; color: #fff;" | Commanders |- | style="vertical-align: top; width: 50%;" | '''[[Allied leaders of World War II|Allied leaders]]:'''<br> [[Joseph Stalin]]<br> [[Franklin D. Roosevelt]]<br> [[Winston Churchill]]<br> [[Chiang Kai-shek]] | style="vertical-align: top; width: 50%;" | '''[[Axis leaders of World War II|Axis leaders]]:'''<br> [[Adolf Hitler]]<br> [[Hirohito]]<br> [[Benito Mussolini]] |- ! colspan="2" style="background-color: #536349; color: #fff;" | Casualties |- | colspan="2" style="text-align: center;" | 60 million to over 75 million deaths<br><small>(military and civilian combined)</small> |} World War II (also called the Second World War) was a global conflict fought from September 1, 1939, to September 2, 1945. It pitted two major alliances against each other: the [[Allies of World War II|Allies]] (led by the [[United Kingdom]], the [[Soviet Union]], the [[United States]], and [[China]]) and the [[Axis powers]] (led by [[Nazi Germany]], [[Fascist Italy]], and the [[Empire of Japan]]). Nearly every country in the world was involved in some way, and many nations committed all of their resources in pursuit of [[total war]]. World War II is the deadliest conflict in human history. Between 70 and 85 million people died, more than half of them civilians. Millions were killed in [[genocide]]s, including [[the Holocaust]], in which Nazi Germany systematically murdered around six million [[Jews]] along with millions of others. The war also saw the first and only use of [[nuclear weapons]] in combat, when the United States dropped [[atomic bombs]] on the Japanese cities of [[Hiroshima]] and [[Nagasaki]] in August 1945. The war's causes stretched back to the aftermath of [[World War I]]. The harsh terms of the [[Treaty of Versailles]] left Germany bitter and economically struggling. The rise of [[fascism]] in Europe and [[militarism]] in Japan pushed the world toward another conflict. Key events leading up to the war included Japan's [[invasion of Manchuria]] in 1931, the [[Spanish Civil War]] (1936–1939), the [[Second Sino-Japanese War]] starting in 1937, and Germany's annexation of [[Austria]] and the [[Sudetenland]] in 1938. After the Allied victory, the [[United Nations]] was created to promote international cooperation and prevent future wars. The [[Soviet Union]] and the [[United States]] emerged as rival [[superpowers]], setting the stage for the decades-long [[Cold War]]. European colonial empires weakened, triggering [[decolonization]] across Africa and Asia. The war fundamentally reshaped the political, economic, and social structures of the entire world. = Background and causes = == The aftermath of World War I == [[World War I]] (1914–1918) had dramatically reshaped Europe. The defeated [[Central Powers]] — including [[Germany]], [[Austria-Hungary]], [[Bulgaria]], and the [[Ottoman Empire]] — lost territory and influence. New nations like [[Poland]], [[Czechoslovakia]], and [[Yugoslavia]] were carved out of the old empires. The [[Russian Empire]] collapsed into revolution and became the [[Soviet Union]]. To prevent another world war, the [[League of Nations]] was established in 1920 through the [[Paris Peace Conference]]. Its goals were to settle disputes through negotiation and to promote disarmament. However, the League lacked enforcement power and would prove unable to stop aggression in the 1930s. == The Treaty of Versailles and the rise of fascism == The [[Treaty of Versailles]] (1919) punished Germany severely. Germany lost about 13 percent of its European territory and all of its overseas colonies. It was forced to pay heavy [[reparations]] (financial penalties) to the Allies and had strict limits placed on the size of its military. These terms created deep resentment among many Germans. During the [[Great Depression]] of the 1930s, economic hardship and political instability pushed people toward extreme political movements. In Germany, [[Adolf Hitler]] and the [[Nazi Party]] rose to power, promising to undo the Versailles Treaty and restore German greatness. Hitler became chancellor in 1933 and quickly established a [[totalitarian]] state (a government with total control over public and private life). He promoted a racist ideology centered on the supposed superiority of an "Aryan" race, and he targeted [[Jews]], [[Slavic peoples]], and other groups as enemies. In Italy, the [[fascism|fascist]] movement under [[Benito Mussolini]] had already seized power in the 1920s. Mussolini promised to make Italy a great power and pursued aggressive expansion, including the [[Second Italo-Ethiopian War|invasion of Ethiopia]] in 1935. In Japan, the military gained increasing control over the government during the 1930s. Japan sought to dominate East Asia and began expanding aggressively, starting with the [[invasion of Manchuria]] in 1931, where it set up the puppet state of [[Manchukuo]]. == Steps toward war == Throughout the mid-1930s, the aggressive moves by Germany, Italy, and Japan met with weak responses from other major powers — a policy known as [[appeasement]]. When Germany remilitarized the [[Rhineland]] in 1936, breaking the Versailles Treaty, Britain and France did nothing. When Italy invaded Ethiopia, the League of Nations imposed limited sanctions that had little effect. Hitler and Mussolini supported the [[Nationalist faction (Spanish Civil War)|Nationalist rebels]] in the [[Spanish Civil War]] (1936–1939), using it as a testing ground for their weapons and tactics. The [[Soviet Union]] supported the opposing Republican government. The Nationalists won, and Spain under dictator [[Francisco Franco]] remained officially neutral during World War II but generally favored the Axis. In July 1937, Japan launched a full-scale [[Second Sino-Japanese War|invasion of China]], capturing major cities including Beijing, Shanghai, and the capital Nanjing. After the fall of Nanjing, Japanese forces committed the [[Nanjing Massacre]], killing tens or hundreds of thousands of Chinese civilians. In March 1938, Germany annexed [[Austria]] (the [[Anschluss]]) with almost no resistance. Then, at the [[Munich Agreement]] in September 1938, Britain and France agreed to let Germany take the [[Sudetenland]] (the German-speaking part of Czechoslovakia) in exchange for Hitler's promise that he would seek no more territory. British Prime Minister [[Neville Chamberlain]] famously declared this would bring "peace for our time." It did not. In March 1939, Germany seized the rest of Czechoslovakia. Alarmed at last, Britain and France pledged to defend [[Poland]] if it were attacked. On August 23, 1939, Germany and the Soviet Union stunned the world by signing the [[Molotov–Ribbentrop Pact]], a non-aggression agreement. Secretly, the pact divided Eastern Europe into German and Soviet "spheres of influence" (areas each power would control). = The war in Europe (1939–1941) = == The invasion of Poland and the Phoney War == On September 1, 1939, Germany [[Invasion of Poland|invaded Poland]], using a new tactic called [[blitzkrieg]] ("lightning war") — fast-moving coordinated attacks using tanks, infantry, and air power. Britain and France declared war on Germany on September 3, but they provided little direct military help to Poland. On September 17, the Soviet Union invaded Poland from the east, as secretly agreed in the Molotov–Ribbentrop Pact. Poland was divided between Germany and the Soviet Union by the end of the month. Despite its military defeat, Poland never formally surrendered. A [[Polish government-in-exile]] was formed, and many Polish soldiers escaped to continue fighting with the Allies. What followed in Western Europe was the so-called "[[Phoney War]]" — months of declared war with almost no actual fighting between Germany and the Western Allies. During this time, the Soviet Union invaded [[Finland]] in November 1939 (the [[Winter War]]), and the Soviets forced the [[Baltic states]] (Estonia, Latvia, Lithuania) to accept Soviet military bases. == The fall of Western Europe == In April 1940, Germany invaded [[Denmark]] and [[Norway]] to secure supply routes for Swedish iron ore. Then, on May 10, 1940, Germany launched its massive assault westward, invading [[Belgium]], the [[Netherlands]], [[Luxembourg]], and [[France]]. Using blitzkrieg tactics and a surprise attack through the [[Ardennes]] forest (which the French thought was impassable for tanks), Germany bypassed France's heavily fortified [[Maginot Line]]. The British Expeditionary Force and portions of the French army were pushed to the coast at [[Dunkirk evacuation|Dunkirk]], where over 300,000 Allied soldiers were evacuated across the English Channel in a dramatic rescue operation. France fell in June 1940, and was divided into German-occupied zones and the collaborationist [[Vichy France]] government in the south. Italy declared war on France and Britain on June 10, 1940, hoping to gain territory from France's collapse. == Britain stands alone == With France defeated, Britain stood virtually alone against Germany. Hitler planned an invasion of Britain ([[Operation Sea Lion]]), but first needed to gain control of the skies. The [[Battle of Britain]] (July–October 1940) was a fierce air campaign between the German [[Luftwaffe]] and the British [[Royal Air Force]] (RAF). The RAF successfully defended British airspace, and Hitler called off the invasion plans. Germany then shifted to nighttime bombing raids on British cities, known as [[the Blitz]], killing tens of thousands of civilians. Meanwhile, the [[Battle of the Atlantic]] raged at sea, as German [[U-boat]]s (submarines) tried to cut off Britain's supply lines by sinking merchant ships. == The Mediterranean and the Balkans == In September 1940, Italy invaded British-held [[Egypt]] from its colony in [[Libya]], starting the [[North African campaign]]. Italy also invaded [[Greece]] in October 1940 but was pushed back into [[Albania]]. Germany intervened in early 1941, conquering [[Yugoslavia]], [[Greece]], and the island of [[Crete]] by May. In North Africa, German General [[Erwin Rommel]] (nicknamed "the Desert Fox") led combined German-Italian forces that pushed the British back toward Egypt. = The war expands (1941) = == Operation Barbarossa == On June 22, 1941, Germany launched [[Operation Barbarossa]], the invasion of the Soviet Union. It was the largest land invasion in history, involving over three million German and Axis soldiers. The attack opened the massive [[Eastern Front (World War II)|Eastern Front]], which would become the deadliest theater of the entire war. The Axis forces made rapid gains during the summer, capturing vast stretches of [[Ukraine]] and the [[Baltic states]] and inflicting enormous casualties on the [[Red Army]]. However, as winter set in, the German advance stalled just outside [[Moscow]]. The Soviets launched a counterattack in December 1941, pushing the Germans back. The failure to capture Moscow marked the end of Germany's blitzkrieg strategy — the war in the east would become a long, grinding struggle. == Pearl Harbor and America enters the war == Meanwhile, tensions had been rising between Japan and the Western powers. Japan's occupation of [[French Indochina]] led the United States, Britain, and the Netherlands to impose an [[oil embargo]] (a ban on selling oil to Japan), which threatened Japan's ability to fuel its military. On December 7, 1941, Japan [[Attack on Pearl Harbor|attacked the American naval base at Pearl Harbor]] in [[Hawaii]], destroying much of the U.S. Pacific Fleet. Simultaneously, Japan attacked British and American territories across Southeast Asia and the Pacific, including the [[Philippines]], [[Malaya]], [[Hong Kong]], and [[Wake Island]]. The United States declared war on Japan on December 8, and Germany and Italy declared war on the United States on December 11. America's entry transformed the war into a truly global conflict. The U.S. and Britain agreed on a "Europe First" strategy — defeating Germany would be the top priority, while fighting a holding action against Japan. By mid-1942, Japan had conquered a vast empire stretching from [[Burma]] to the [[Dutch East Indies]] to the western Pacific islands. = The tide turns (1942–1943) = == Key battles == Three major turning points shifted the war in the Allies' favor: '''The Battle of Midway (June 1942):''' In the Pacific, the U.S. Navy ambushed a Japanese fleet near [[Midway Island]], sinking four Japanese aircraft carriers. This decisive victory halted Japan's naval expansion and gave the U.S. the initiative in the Pacific. '''The Battle of Stalingrad (August 1942 – February 1943):''' On the Eastern Front, Germany pushed deep into southern Russia, aiming to capture the oil fields of the [[Caucasus]]. The German Sixth Army became locked in brutal street-by-street fighting in the city of [[Stalingrad]] (now Volgograd). In November 1942, the Soviets launched a massive counterattack that encircled the German forces. After months of starvation and combat, the remaining German troops surrendered in February 1943. Stalingrad was one of the bloodiest battles in history and is widely considered the turning point of the war in Europe. '''El Alamein and North Africa (October 1942 – May 1943):''' In [[Egypt]], British forces under General [[Bernard Montgomery]] defeated Rommel's Afrika Korps at the [[Second Battle of El Alamein]] in October–November 1942. Combined with the Anglo-American landings in French North Africa ([[Operation Torch]]) in November 1942, this led to the complete Axis defeat in North Africa by May 1943. == The invasion of Italy == With North Africa secured, the Allies [[Allied invasion of Sicily|invaded Sicily]] in July 1943. The invasion triggered the overthrow of Mussolini, and Italy signed an [[armistice]] (ceasefire agreement) with the Allies in September 1943. However, Germany quickly occupied most of Italy, rescued Mussolini, and set up a puppet state in the north called the [[Italian Social Republic]]. The Allies fought their way slowly up the Italian peninsula against strong German defenses. == The Eastern Front turns == After Stalingrad, the initiative on the Eastern Front shifted permanently to the Soviet Union. In July 1943, Germany attempted one last major offensive at the [[Battle of Kursk]], the largest tank battle in history. The well-prepared Soviet defenses held, and the counterattack that followed began a relentless Soviet advance westward that would continue until the war's end. = Allied victory (1944–1945) = == D-Day and the liberation of France == On June 6, 1944 — known as [[D-Day]] — the Allies launched [[Operation Overlord]], the largest amphibious (sea-to-land) invasion in history. Over 150,000 Allied soldiers landed on the beaches of [[Normandy]], France. Despite heavy casualties, the invasion succeeded, and the Allies established a foothold in Western Europe. Paris was liberated in August 1944, and Allied forces pushed eastward toward Germany. In December 1944, Germany launched a last-ditch counteroffensive in the [[Ardennes]] forest in Belgium, known as the [[Battle of the Bulge]]. It was the largest battle the U.S. Army fought in the war, but after initial German success, the Allies pushed them back. == The Soviet advance == On the Eastern Front, the Soviets launched a massive summer offensive in June 1944 called [[Operation Bagration]], which destroyed the German Army Group Center and liberated [[Belarus]]. By early 1945, Soviet forces had pushed into Poland, Romania, Bulgaria, Hungary, and were closing in on Germany itself. == The fall of Germany == By spring 1945, Allied forces were closing in from both east and west. The Western Allies crossed the [[Rhine River]] in March 1945. The Soviets launched their final assault on [[Battle of Berlin|Berlin]] in April. On April 30, 1945, with Soviet troops just blocks from his underground bunker, [[Adolf Hitler]] committed suicide. Germany surrendered unconditionally on May 7–8, 1945, a date celebrated as [[Victory in Europe Day|V-E Day]] (Victory in Europe Day). == The war in the Pacific == While the war in Europe raged, the Allies had been steadily pushing back Japan in the Pacific using an "[[island hopping]]" strategy — capturing key islands and bypassing others to get closer to Japan. Major Pacific battles included [[Guadalcanal Campaign|Guadalcanal]] (1942–1943), the [[Philippines|reconquest of the Philippines]] (1944–1945), [[Battle of Iwo Jima|Iwo Jima]] (February–March 1945), and [[Battle of Okinawa|Okinawa]] (April–June 1945). Japanese resistance was fierce, with many soldiers fighting to the death and [[kamikaze]] pilots deliberately crashing their planes into Allied ships. By mid-1945, massive Allied bombing raids had devastated Japanese cities, and a naval blockade had cut off Japan's imports. Still, Japan refused to surrender unconditionally. == Atomic bombs and Japan's surrender == On August 6, 1945, the United States dropped an atomic bomb called "[[Little Boy]]" on [[Hiroshima]], killing an estimated 80,000 people instantly (with tens of thousands more dying later from radiation). On August 9, a second bomb called "[[Fat Man]]" was dropped on [[Nagasaki]], killing around 40,000 people instantly. On August 8, the Soviet Union declared war on Japan and invaded Japanese-held [[Manchuria]], quickly defeating the Japanese forces there. Faced with the atomic bombs, the Soviet invasion, and the prospect of further destruction, [[Emperor Hirohito]] of Japan announced the country's surrender on August 15, 1945 ([[Victory over Japan Day|V-J Day]]). The formal surrender documents were signed on September 2, 1945, aboard the [[USS Missouri]] in [[Tokyo Bay]], officially ending World War II. = The Holocaust and war crimes = == The Holocaust == [[The Holocaust]] was the systematic, state-sponsored murder of approximately six million Jews by Nazi Germany and its collaborators. The Nazis also targeted [[Roma people]], [[Slavic peoples]], disabled people, [[homosexuality|homosexuals]], political opponents, and others — bringing the total number of victims to 11 to 17 million. The killing was carried out through mass shootings, forced labor, starvation, and [[extermination camps]] such as [[Auschwitz]], [[Treblinka]], and [[Sobibor]], where victims were murdered in gas chambers on an industrial scale. == Other war crimes == Japan committed widespread atrocities in occupied territories, including the [[Nanjing Massacre]], the use of [[comfort women]] (forced sex slaves), brutal treatment of [[prisoner of war|prisoners of war]], and medical experiments on prisoners (notably at [[Unit 731]]). The Soviet Union also committed atrocities, including the [[Katyn massacre]] (the killing of thousands of Polish officers) and mass deportations of ethnic groups. After the war, German leaders were tried for war crimes at the [[Nuremberg Trials]], and Japanese leaders faced the [[International Military Tribunal for the Far East]] in Tokyo. = Aftermath and legacy = == Political changes == World War II fundamentally reshaped the world order. The [[United Nations]] was established on October 24, 1945, to promote international cooperation and prevent future wars. The five major Allied powers — the United States, the Soviet Union, the United Kingdom, France, and China — became the permanent members of the [[United Nations Security Council|UN Security Council]], each with [[veto]] power. Germany was divided into four occupation zones controlled by the U.S., Britain, France, and the Soviet Union. This division eventually led to the creation of two separate countries: [[West Germany]] (aligned with the Western democracies) and [[East Germany]] (a Soviet-backed communist state). They would not reunify until 1990. Japan was occupied by American forces under General [[Douglas MacArthur]]. A new democratic constitution was adopted, and Japan renounced war as a means of settling international disputes. == The Cold War == The wartime alliance between the Western powers and the Soviet Union quickly broke down. The United States and the Soviet Union emerged as rival [[superpowers]] with opposing ideologies — [[capitalism]] and [[democracy]] versus [[communism]]. This rivalry, known as the [[Cold War]], dominated global politics for nearly half a century (1947–1991) and led to the formation of the U.S.-led [[NATO]] and the Soviet-led [[Warsaw Pact]]. == Decolonization == The war weakened European colonial powers, accelerating the process of [[decolonization]]. In the decades following the war, dozens of countries in Africa, Asia, and the Middle East gained independence from European rule. In some cases this happened peacefully; in others, like in [[Algeria]] and [[Vietnam]], it involved bitter wars of independence. == Economic recovery == The United States, which emerged from the war with its homeland largely undamaged, became the world's dominant economic power. Through the [[Marshall Plan]] (1948–1952), the U.S. provided about $13 billion (around $170 billion in today's dollars) to help rebuild Western Europe. Japan and West Germany also experienced remarkable economic recoveries in the postwar decades. = Key figures = The war involved many influential leaders on both sides: '''Allied leaders:''' [[Franklin D. Roosevelt]] and later [[Harry S. Truman]] (United States), [[Winston Churchill]] (United Kingdom), [[Joseph Stalin]] (Soviet Union), [[Charles de Gaulle]] (Free France), [[Chiang Kai-shek]] (China) '''Axis leaders:''' [[Adolf Hitler]] (Nazi Germany), [[Benito Mussolini]] (Fascist Italy), [[Hideki Tojo]] and [[Emperor Hirohito]] (Japan) '''Military commanders:''' [[Dwight D. Eisenhower]], [[Douglas MacArthur]], [[George S. Patton]] (U.S.); [[Bernard Montgomery]] (UK); [[Georgy Zhukov]] (Soviet Union); [[Erwin Rommel]] (Germany); [[Isoroku Yamamoto]] (Japan) = By the numbers = The scale of World War II was unprecedented: '''Deaths:''' 70–85 million total (including about 50 million civilians) '''Duration:''' 6 years (1939–1945 in Europe; related fighting in Asia from 1937) '''Countries involved:''' Over 30 nations formally at war; nearly every country affected '''Cost:''' The U.S. alone spent an estimated $296 billion (1945 dollars) — about $4.9 trillion in today's money '''The Soviet Union''' suffered the most casualties of any nation, losing approximately 27 million people — roughly one in seven of its entire population. {{Notelist}}