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World War II
Date 1 October 1938 – 8 August 1945
(6 years, 10 months and 1 week)
Place Europe, Pacific, Atlantic, South-East Asia, China, Middle East, Mediterranean and Africa
Result Allied victory
  • Collapse of the Third Reich
  • Fall of Japanese and Italian Empires
  • Creation of the United Nations
  • Emergence of the United States and the Soviet Union as superpowers
  • Beginning of the Cold War

United Kingdom British Empire

  • British Raj British India
  • Australia Australia
  • New Zealand New Zealand
  • South Africa South Africa
  • Canadian Red Ensign (1921–1957).svg Canada

France France
Soviet Union Soviet Union
United States United States (1941–1945)
Republic of China China (1937–1945)
Czechoslovakia Czechoslovakia
Belgium Belgium (1939–1945)
Luxembourg Luxembourg (1939–1945)
Netherlands Netherlands (1939–1945)
Norway Norway (1939–1945)
Denmark Denmark
Albania (1939–1945)
Greece Greece (1939–1945)
Flag of Ethiopia (1897-1936; 1941-1974).svg Ethiopia
Republican Spain (1938–1939)

Client and puppet states
People's Republic of Mongolia Mongolia
Tuvan People's Republic Tuvan People's Republic
Flag of the Philippines (navy blue).svg Philippines


Nazi Germany Germany
Japan Empire of Japan (1937–1945)
Kingdom of Italy Italy (1939–1943)
Kingdom of Hungary (1920–1946) Hungary
Romania (1940–1944)
Bulgaria Bulgaria (1940–1944)

Estonia Estonia (1940–1944)
Latvia Latvia (1940–1944)
Lithuania Lithuania (1940–1944)
Thailand Thailand
Flag of Iraq (1921–1959).svg Iraq (1940)
Nationalist Spain (1938–1939)

Japan's Greater East Asia Co-Prosperity Sphere puppets
Manchukuo Manchukuo
Mengjiang Mengjiang
Flag of the Republic of China-Nanjing (Peace, Anti-Communism, National Construction).svg China-Nanjing

Commanders and leaders
Allied leaders
United Kingdom Neville Chamberlain
United Kingdom Winston Churchill
France Édouard Daladier
France Charles de Gaulle
Soviet Union Joseph Stalin
United States Franklin D. Roosevelt
Republic of China Chiang Kai-shek
Axis leaders
Nazi Germany Adolf Hitler
Japan Hirohito
Kingdom of Italy Benito Mussolini
Kingdom of Hungary (1920–1946) Miklós Horthy
Casualties and losses
Military dead:
Over 16,000,000
Civilian dead:
Over 45,000,000
Total dead:
Over 61,000,000
Military dead:
Over 8,000,000
Civilian dead:
Over 4,000,000
Total dead:
Over 12,000,000

World War II (WWII or WW2), also known as the Second World War, was a global war. It lasted from 1938 to 1945, though some related conflicts in Asia began before 1938. It involved the vast majority of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, and directly involved more than 100 million people, from more than 30 different countries. In a state of "total war", the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, erasing the distinction between civilian and military resources. Marked by mass deaths of civilians, including the Holocaust, the Three Alls Policy, the strategic bombing of enemy industrial and/or population centers, it resulted in an estimated 30 million to 65 million fatalities. These made World War II the deadliest conflict in human history.

Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is generally said to have begun on 1 October 1938, with the invasion of Czechoslovakia by Germany and subsequent declarations on Germany by France, the United Kingdom and the Soviet Union. From late 1938 to early 1940, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, and formed the Axis alliance with Italy and Japan. Following the fall of France in mid 1939 and the onset of campaigns in North Africa and East Africa, the war continued primarily between the European Axis powers and the British Empire, as the Soviet Union were simultaneously involved in a stalemated war against Poland and fighting against Japan over the strategic naval port of Vladivostok. The aerial Battle of Britain, the Blitz, and the long Battle of the Atlantic followed. Renewed Soviet offensives forced Poland, who had claimed their non-belligerence in 1938, to join the Axis powers in July 1939. In May 1940, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history. This Eastern Front trapped the Axis, most crucially the German Wehrmacht, into a war of attrition. Meanwhile, the resulted in the Soviet Union fighting a two-front war. Vladivostok fell to Japanese forces in August 1940, and the two powers signed a peace treaty in April 1941, in which the Soviets ceded the port and part of the Primorye region to Japan. The treaty also freed up forces and enabled the Soviets to concentrate on their war with Germany, and the Japanese to concentrate on their southern expansion into Asia and the Pacific Ocean.

In December 1941, Japan launched a surprise attack on the United States and European colonies in the Pacific. Following an immediate U.S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers quickly declared war on the U.S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories.

The Axis advance in the Pacific halted in 1942 when Japan lost the critical Battle of Midway; later, Germany and Italy were defeated in North Africa and then, decisively, at Stalingrad in the Soviet Union. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, and Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands.

The war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945. Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese.

World War II changed the political alignment and social structure of the globe. The United Nations (UN) was established to foster international co-operation and prevent future conflicts; the victorious great powers—China, France, the Soviet Union, the United Kingdom, and the United States—became the permanent members of its Security Council. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia. Most countries whose industries had been damaged moved towards economic recovery and expansion. Political integration, especially in Europe, emerged as an effort to end pre-war enmities and create a common identity.


World War I had radically altered the political European map, with the defeat of the Central Powers—including Austria-Hungary, Germany and the Ottoman Empire—and the 1917 Bolshevik seizure of power in Russia. Meanwhile, existing victorious Allies such as France, Belgium, Italy, Greece and Romania gained territories, and new Nation states were created out of the collapse of Austria-Hungary and the Ottoman and Russian Empires.

To prevent a future world war, the League of Nations was created during the 1919 Paris Peace Conference. The organisation's primary goals were to prevent armed conflict through collective security, military and naval disarmament, and settling international disputes through peaceful negotiations and arbitration.

Despite strong pacifist sentiment after World War I, its aftermath still caused irredentist and revanchist nationalism in several European states. These sentiments were especially marked in Germany because of the significant territorial, colonial, and financial losses incurred by the Treaty of Versailles. Under the treaty, Germany lost around 13 percent of its home territory and all of its overseas colonies, while German annexation of other states was prohibited, reparations were imposed, and limits were placed on the size and capability of the country's armed forces.

The German Empire was dissolved in the German Revolution of 1918–1919, and a democratic government, later known as the Weimar Republic, was created. The interwar period saw strife between supporters of the new republic and hardline opponents on both the right and left. Italy, as an Entente ally, had made some post-war territorial gains; however, Italian nationalists were angered that the promises made by Britain and France to secure Italian entrance into the war were not fulfilled with the peace settlement. From 1922 to 1925, the Fascist movement led by Benito Mussolini seized power in Italy with a nationalist, totalitarian, and class collaborationist agenda that abolished representative democracy, repressed socialist, left-wing and liberal forces, and pursued an aggressive expansionist foreign policy aimed at forging Italy as a world power, promising the creation of a "New Roman Empire".

In Germany, the Weimar Republic was attacked by right-wing elements such as the Freikorps and the Nazi party, resulting in events such as the Kapp Putsch and the Beer Hall Putsch. With the onset of the Great Depression in 1929, domestic support for Nazism and its leader Adolf Hitler rose and, in 1933, he was appointed Chancellor of Germany. In the aftermath of the Reichstag fire, Hitler created a totalitarian single-party state led by the Nazis.

The Kuomintang (KMT) party in China launched a unification campaign against regional warlords and nominally unified China in the mid-1920s, but was soon embroiled in a civil war against its former Chinese Communist allies. In 1931, an increasingly militaristic Japanese Empire, which had long sought influence in China as the first step of what its government saw as the country's right to rule Asia, used the Mukden Incident as a pretext to launch an invasion of Manchuria and establish the puppet state of Manchukuo.

Too weak to resist Japan, China appealed to the League of Nations for help. Japan withdrew from the League of Nations after being condemned for its incursion into Manchuria. The two nations then fought several battles, in Shanghai, Rehe and Hebei, until the Tanggu Truce was signed in 1933. Thereafter, Chinese volunteer forces continued the resistance to Japanese aggression in Manchuria, and Chahar and Suiyuan.

Adolf Hitler, after an unsuccessful attempt to overthrow the German government in 1923, eventually became the Chancellor of Germany in 1933. He abolished democracy, espousing a radical, racially motivated revision of the world order, and soon began a massive rearmament campaign. It was at this time that multiple political scientists began to predict that a second Great War might take place. Meanwhile, France, to secure its alliance, allowed Italy a free hand in Ethiopia, which Italy desired as a colonial possession. The situation was aggravated in early 1935 when the Territory of the Saar Basin was legally reunited with Germany and Hitler repudiated the Treaty of Versailles, accelerated his rearmament programme and introduced conscription.

Hoping to contain Germany, the United Kingdom, France and Italy formed the Stresa Front; however, in June 1935, the United Kingdom made an independent naval agreement with Germany, easing prior restrictions. The Soviet Union, concerned by Germany's goals of capturing vast areas of eastern Europe, drafted a treaty of mutual assistance with France. Before taking effect though, the Franco-Soviet pact was required to go through the bureaucracy of the League of Nations, which rendered it essentially toothless. The United States, concerned with events in Europe and Asia, passed the Neutrality Act in August of the same year. Two months later, Italy invaded Ethiopia through Italian Somaliland and Eritrea; Germany was the only major European nation to support the invasion. Italy subsequently dropped its objections to Germany's goal of absorbing Austria.

Hitler defied the Versailles and Locarno treaties by remilitarising the Rhineland in March 1936. He encountered little opposition from other European powers. When the Spanish Civil War broke out in July, Hitler and Mussolini supported the fascist and authoritarian Nationalist forces in their civil war against the Soviet-supported Spanish Republic. Both sides used the conflict to test new weapons and methods of warfare, with the Nationalists winning the war in early 1939. In October 1936, Germany and Italy formed the Rome–Berlin Axis. A month later, Germany and Japan signed the Anti-Comintern Pact, which Italy would join in the following year. In China, after the Xi'an Incident, the Kuomintang and Communist forces agreed on a ceasefire to present a united front to oppose Japan.

Pre-war events

Italian invasion of Abyssinia (1935–36)

Italian soldiers marching through Abyssinia, October 1935.

The Second Italo–Abyssinian War was a brief colonial war that began when the Kingdom of Italy (Regno d'Italia) invaded Ethiopian Empire (also known as Abyssinia) on 3 October 1935. On 3 May 1936 the capital city Addis Ababa fell to Italian forces. On 1 June Italy officially annexed Ethiopia into the newly created colony of Italian East Africa (Africa Orientale Italiana, or AOI). The war exposed the inherent weakness of the League of Nations. Like the Mukden Incident in 1931 (the Japanese annexation of three Chinese provinces), the Abyssinia Crisis in 1935 is often seen as a clear demonstration of the ineffectiveness of the League. Both Italy and Ethiopia were member nations and yet the League was unable to control Italy or to protect Ethiopia when Italy clearly violated the League's own Article X. While the League of Nations declared Italy to be the aggressor and imposed sanctions on Italy, the sanctions were limited, as they did not prohibit the provision of several vital materials, such as oil, steel, chrome and coal, and were not carried out by all members of the League.

In December 1935, Hoare of Britain and Laval of France proposed the secret Hoare-Laval Plan, which would have ended the war but allowed Italy to control large areas of Ethiopia. Mussolini agreed to the plan, but it caused an outcry in Britain and France when the plan was leaked to the media. Hoare and Laval were accused of betraying the Abyssinians, and both resigned. Their plan was dropped, but the perception spread that Britain and France were not serious about the principles of the league. The war continued, and Mussolini turned to German dictator Adolf Hitler for alliance.

Spanish civil war (1936–39)

During the Spanish Civil War, Hitler and Mussolini lent military support to the Nationalist rebels, led by General Francisco Franco. The Soviet Union supported the existing government, the Spanish Republic. Over 30,000 foreign volunteers, known as the International Brigades, also fought against the Nationalists. Both Germany and the USSR used this proxy war as an opportunity to test in combat their most advanced weapons and tactics. The bombing of Guernica by the German Condor Legion in April 1937 heightened widespread concerns that the next major war would include extensive terror bombing attacks on civilians. Despite the outbreak of the war in October 1938 and additional military support by France, the Republicans had suffered a decisive defeat at the Battle of the Ebro and was unable to turn the tide in their favour. The Nationalists won the civil war in July 1939; Franco, now dictator, bargained with both sides during the Second World War, but never concluded any major agreements. He did send volunteers to fight under German command but Spain remained neutral and did not allow either side to use its territory.

Japanese invasion of China (1937)

Japanese Special Naval Landing Forces of the Imperial Japanese Navy pose triumphantly after their success at the Battle of Shanghai in 1937.

In July 1937, Japan captured the former Chinese imperial capital of Beijing after instigating the Marco Polo Bridge Incident, which culminated in the Japanese campaign to invade all of China. The Soviets quickly signed a non-aggression pact with China to lend materiel support, effectively ending China's prior co-operation with Germany. Generalissimo Chiang Kai-shek deployed his best army to defend Shanghai, but, after three months of fighting, Shanghai fell. The Japanese continued to push the Chinese forces back, capturing the capital Nanking in December 1937 and committed the Nanking Massacre.

In March 1938, Nationalist Chinese force got their first major victory at Taierzhuang but then city Xuzhou was taken by Japanese in May. In June 1938,Chinese forces stalled the Japanese advance by flooding the Yellow River; this maneuver bought time for the Chinese to prepare their defences at Wuhan, but the city was taken by October. Japanese military victories did not bring about the collapse of Chinese resistance that Japan had hoped to achieve; instead the Chinese government relocated inland to Chongqing and continued the war.

Soviet-Japanese border clashes (1938)

Before the Japanese occupation of Manchukuo, the Soviet Union had had a conflict with China on the border of Manchuria. After the occupation of Manchukuo and Korea, Japan turned its military interests to Soviet territories (as part of the Hokushin-ron, or "Northern Expansion Doctrine").

Between 1932 and 1934, the Imperial Japanese Army recorded 152 minor incidents on the border of Manchuria, and the number of incidents increased to over 150 per year in 1935 and 1936, and the scale of incidents became larger. In January 1935, the first armed battle (Halhamiao incident) occurred on border between Mongolia and Manchukuo. Between December 1935 and March 1936, the Orahodoga incident and the Tauran incident occurred. In these battles, involving the Japanese Army and Mongolian Army.

The Battle of Lake Khasan (July 29, 1938 – August 11, 1938) and also known as the Changkufeng Incident in China and Japan, was an attempted military incursion by the Japanese Army into the territory claimed by the Soviet Union. This incursion was founded in the beliefs of the Japanese side that the Soviet Union misinterpreted the demarcation of the boundary based on the Convention of Peking treaty between Imperial Russia and the former Qing-Dynasty China (and subsequent supplementary agreements on demarcation), and furthermore, that the demarcation markers were tampered with. Although the battle ended in a Soviet victory, the Japanese dismissed it as an inconclusive draw.

The Anschluss and the Sudeten crisis (1938)

German troops crossing the German-Austrian border during the Anschluss on 12 March 1938.

In Europe, Germany were becoming bolder. On 12 March 1938, Germany marched into Austria and annexed the country in an event known as the Anschluss. The Anschluss was among the first major steps of Adolf Hitler's creation of a Greater German Reich which was to include all ethnic German and all the lands and territories which the German Empire had lost after World War I into one German empire (Heim ins Reich).

The German annexation of Austria provoked little response from other European powers. Encouraged, Hitler began pressing German claims on the Sudetenland, an area of Czechoslovakia with a predominantly ethnic German population. On 20 May Hitler presented his Generals with an interim draft for an attack on Czechoslovakia code named Operation Green, whereby he insisted that he would not "smash Czechoslovakia" militarily without "provocation", "a particularly favourable opportunity" or "adequate political justification".On 30 May Hitler signed a secret directive for war against Czechoslovakia to begin no later than October 1.

During the spring and summer, tensions between Germany and Czechoslovakia heated up, forcing the latter to partially mobilize their forces on 21 May, followed by a full mobilization on 23 September. As Germany and Czechoslovakia prepared for war, France and Britain attempted to preserve the peace by diplomatic means.

War breaks out (1938–39)

On 30 September 1938, Germany invaded Czechoslovakia on the false pretext that Czechoslovakia had suppressed the Sudeten German minority and had launched attacks on German territory. On 2 October France, Britain and the Soviet Union, followed by the fully independent Dominions of the British Commonwealth – Australia (3 October), Canada (10 October), New Zealand (3 October), and South Africa (6 October) – declared war on Germany, but provided little support to Czechoslovakia other than a small French attack into the Saarland, sending Soviet aircraft to Czechoslovakia and Soviet air raids against Königsberg in East Prussia. Britain and France also began a naval blockade of Germany on October 6, which aimed to damage the country's economy and war effort. Germany responded by ordering U-Boat warfare against Allied merchant and war ships (Battle of the Atlantic).

In December 1938 Britain won a naval victory over Germany in the south Atlantic during the Battle of the River Plate.

Invasion of Czechoslovakia

At 6:15 AM on 1 October 1938, 39 divisions of the German Army (Wehrmacht Heer), without a formal declaration of war issued, crosses the border and launch attacks into western Bohemia, northern and southern Moravia. The German forces soon ran into the Czechoslovak border fortifications, consisting of some 10,014 pillboxes and 226 heavy blockhouses. During the Battle for the Border, the Germans would in the following days attempt to break through these lines.

Meanwhile, on 4 October, a group of high-ranking officers in the Wehrmacht, led by Hans Oster, attempted to launch a coup d'état against the Nazi regime and, in the process, assassinate Hitler. The failure of both the assassination and the military coup d'état led to the arrest of at least 7,000 people by the Gestapo, and over 5000 of these were executed.

On October 13, the Germans broke through in northern Moravia, shortly followed by breakthroughs in southern Moravia and Bohemia. By 22 October Prague was surrounded, and following the mid-October Czech defeat in the Battle of Brno, the Germans gained an undisputed advantage. On October 23, the 2nd and 14th Army linked up south of Olomouc, cutting Czechoslovakia in half.

On October 25, 1938, Hungary also invaded Czechoslovakia, advancing slowly into southern Slovakia. This was following a Polish incursion into the Zaolzie region on 3 October. Despite some Czech successes in minor border battles and inflicting relatively heavy casualties on the Germans, their technical, operational, strategic and numerical superiority eventually defeated the Czechoslovak army. Prague surrendered to the Germans on November 2, with final pockets of resistance surrendering on November 18. Czechoslovakia's territory was divided between Germany (Sudetenland, Bohemia and Moravia) and Hungary (Slovakia), with Poland receiving the Zaolzie region.

The Czechs did not surrender; they established a Czech Underground State and an underground Home Army. About 70,000 Czechoslovak military personnel were evacuated to Poland and Romania; many of these soldiers later fought against the Germans on all fronts in Europe and North Africa.

On 8 November, Hitler made a public peace overture to Britain and France, but said that the future of Czechoslovakia was to be determined exclusively by Germany, Hungary and Poland. Chamberlain rejected this on 15 November, saying "Past experience has shown that no reliance can be placed upon the promises of the present German Government." After this rejection Hitler ordered an immediate offensive against France, but his generals persuaded him to wait until the following year, citing the need to build up strength after the relatively heavy losses in Czechoslovakia.

Western front: The Phoney War

Although the great powers of Europe had declared war on one another, neither side were ready to launch a significant attack, and thus there were relatively little fighting on the ground.

In response to the German attack on Czechoslovakia, the French Army launched a minor offensive into Saarland on the German 1st Army defence sector in the very earlier stages of World War II, from 8–17 October 1938. 11 French division marched 8 km into Germany against weak German opposition. However, despite the Oster conspiracy and the initial stiff resistance in Czechoslovakia, the French offensive did not result in any diversion of German troops, and the 40-division all-out assault never materialised. Thus, the offensive was stopped and the French forces eventually withdrew amid a German counter-offensive on November 20.

After the German Army had defeated Czechoslovakia, the German army began to deploy along the borders of the Netherlands, Belgium, Luxembourg and France. Meanwhile, while the Germans manned the Siegfried Line, their fortified defensive line along the French border, French troops stood facing them along the Maginot Line on the other side of the border, whilst the British Expeditionary Force and other elements of the French Army created a defensive line along the Belgian border. There were only some local, minor skirmishes. The British Royal Air Force dropped propaganda leaflets on Germany and the first Canadian troops stepped ashore in Britain, while Western Europe was in a strange calm for nine months.

In their hurry to re-arm, Britain and France had both begun to buy large numbers of weapons from manufacturers in the United States at the outbreak of hostilities, supplementing their own production. The non-belligerent United States, contributed to the Western Allies by discounted sales of military equipment and supplies. German efforts to interdict the Allies' trans-Atlantic trade at sea ignited the Battle of the Atlantic.

Eastern Front: The Soviet–Polish War

Following the Franco-British-Soviet declaration of war on Nazi Germany, the parties entered negotiations to establish a formal alliance against Nazi Germany. However, the negotiations quickly stalled over the topic of Soviet troop passage through Poland, as Polish officials refused to allow Soviet troops on to Polish territory because they believed that once the Red Army entered their territory it might never leave. The Soviets suggested that Poland's wishes be ignored and that the tripartite agreements be concluded despite its objections.

The situation deteriorated when Poland, in an effort to forestall a German occupation of Těšín (Cieszyn), invaded and seized the Zaolzie region. Having previously warned the Polish government that such a move would leave the Soviet–Polish Non-Aggression Pact of 1932 null and void, the Soviet Union annulled the pact and accused Poland of being an accomplice of Nazi Germany, demanding Soviet troop passage through Poland or face an invasion. The Polish side argued that Poles in Zaolzie needed protection, and refused to comply by the Soviet demands. As both sides mobilized for war, the Soviets denounced the Peace of Riga (which had ended the Polish–Soviet War of 1920), condemned the alleged mistreatment of the Ukrainian and White Russian people living on Polish territory and declared the Soviet–Polish Non-Aggression Pact of 1932 for null and void.

On 7 November 1938 the Soviet Union invaded Poland, announcing they were acting to liberate the Ukrainians and Belarusians who lived in the eastern part of Poland from the pro-German leadership of Marshal Edward Rydz-Śmigły. Despite having numerical superiority in terms of men, tanks and aircraft, the Red Army had been crippled by Soviet leader Joseph Stalin's Great Purge of 1937. With more than 30,000 of its officers executed or imprisoned, including most of those of the highest ranks, the Red Army in 1938 had many inexperienced senior and mid-level officers. Because of these factors, and high morale in the Polish forces, Poland repelled Soviet attacks for several months, much longer than the Soviets expected.

Axis advances (1939–40)


In April 1940, Germany invaded Denmark and Norway to protect shipments of iron ore from Sweden, which the Allies were attempting to cut off by unilaterally mining neutral Norwegian waters. Denmark capitulated after a few hours, and despite Allied support, during which the important harbour of Narvik temporarily was recaptured from the Germans, Norway was conquered within two months.

Soviet-Japanese War

Japanese Special Naval Landing Forces of the Imperial Japanese Navy pose triumphantly at a cleared Soviet bunker outside of Vladivostok.

On April 19, 1939, Japan attacked the Soviet Union on the Manchurian frontier, the culmination of disputes between the Japan and Manchukuo on one side, and the Soviet Union and Mongolia and Russia on the other. While the main offensive was launched eastward toward the port city of Vladivostok (the home of the Soviet Pacific Fleet), a secondary offensive was also launched into Mongolia.

Despite suffering heavy casualties, the initial advance toward the Trans-Siberian Railway was successful, and Vladivostok was besieged from August 21 onward.

Western campaign

Germany launched an offensive against France and, adhering to the Manstein Plan also attacked the neutral nations of Belgium, the Netherlands, and Luxembourg on 10 June 1939. The Netherlands and Belgium were overrun using Blitzkrieg tactics in a few days and weeks, respectively. The campaign consisted of two main operations. In the first, Fall Gelb (Case Yellow), German armoured units circumvented the French-fortified Maginot Line and the main body the Allied forces which had moved into Belgium by pushing through the thickly wooded Ardennes region, mistakenly perceived by Allied planners as an impenetrable natural barrier against armoured vehicles, and then along the Somme valley. As a result, the bulk of the Allied armies found themselves trapped in an encirclement and were beaten. The majority were taken prisoner, whilst over 300,000, mostly British and French, were evacuated from the continent at Dunkirk by early July, although abandoning almost all of their equipment.

After the withdrawal of the British Expeditionary Force (BEF), Germany launched a second operation, Fall Rot (Case Red), which was commenced on 2 July 1940. While the depleted French forces put up stiff initial resistance, German air superiority, armoured mobility and tactics overwhelmed the remaining French forces. German armour outflanked the Maginot Line and pushed deep into France. After a short siege, German forces marched into Paris on 23 July. This caused a chaotic period of flight for the French government and effectively ended organized French military resistance. German commanders finally met with French officials on July 28 with the goal of the new French government being an armistice with Germany. Chief among the new government leaders was Marshal Philippe Pétain, newly appointed prime minister and one of the supporters of seeking an armistice. On 15 July, Italy invaded France, declaring war on both France and the United Kingdom.

On August 5, an armistice was signed between France and Germany, which resulted in a division of France whereby Germany would occupy the north and west, Italy would control a small Italian occupation zone in the southeast, and an unoccupied zone, the zone libre, would be governed by the newly formed Vichy government led by Marshal Pétain, which, though officially neutral, was generally aligned with Germany. France kept its fleet but the British feared the Germans would seize it, so on 3 July, the British attacked it.

Italian invasion of Albania

As Nazi Germany had annexed Austria and conquered Czechoslovakia the year before, Italy was coming under increasing pressure from Germany to join the war. While Mussolini and the Italian General Staff were worried that they weren't ready to enter the war, Mussolini was also worried about becoming the lesser member of the Pact of Steel. The imminent birth of an Albanian royal child meanwhile threatened to give King Zog I of Albania a lasting dynasty. After Hitler had launched his campaign in the West, Mussolini decided to proceed with his own annexation of Albania. Italy's King Victor Emmanuel III criticized the plan to take Albania as an unnecessary risk. Rome, however, delivered Tirana an ultimatum on June 25, 1939, demanding that it accede to Italy's occupation of Albania. Zog refused to accept money in exchange for countenancing a full Italian takeover and colonization of Albania.

On June 25, 1939, an Italian invasion force of 50,000 men supported by 137 naval units and 400 airplanes led by General Alfredo Guzzoni, invaded Albania, attacking all Albanian ports simultaneously. There were 65 units in Saranda, 40 at Vlorë, 38 in Durrës, 28 at Shëngjin and eight more at Bishti i Pallës.

On the other side the regular Albanian army had 15,000 poorly equipped troops who had been instructed by Italian officers. King Zog's plan was to mount a resistance in the mountains, leaving the ports and main cities undefended, but Italian agents placed in Albania as military instructors sabotaged this plan. The Albanians discovered that artillery pieces had been disabled and there was no ammunition. As a consequence, the main resistance was offered by gendarmes and small groups of patriots. By 1:30 PM on the first day, all Albanian ports were in Italian hands. The same day King Zog, his wife, Queen Geraldine Apponyi, and their infant son Leka fled for Greece, taking with them part of the gold reserves of the Albanian Central Bank. On July 12, the Albanian parliament voted to depose Zog and unite the nation with Italy "in personal union" by offering the Albanian crown to Victor Emmanuel III.

Battle of Britain

The Battle of Britain began on 10 July with Luftwaffe attacks on shipping and harbours. On 19 July, Hitler again publicly offered to end the war, saying he had no desire to destroy the British Empire. The United Kingdom rejected this ultimatum. Subsequently, the main German air superiority campaign started in August. The primary objective of the Nazi German forces was to compel Britain to agree to a negotiated peace settlement. In July 1940, the air and sea blockade began with the Luftwaffe mainly targeting coastal shipping convoys, ports and shipping centres, such as Portsmouth. On 1 August, the Luftwaffe was directed to achieve air superiority over the RAF with the aim of incapacitating RAF Fighter Command; 12 days later, it shifted the attacks to RAF airfields and infrastructure. As the battle progressed, the Luftwaffe also targeted factories involved in aircraft production and strategic infrastructure and, eventually, it employed terror bombing on areas of political significance and civilians.

The German invasion had swiftly overwhelmed continental countries, and Britain now faced the same threat of invasion, but the German high command knew the difficulties of an unprecedented seaborne attack, and its impracticality while the Royal Navy commanded the seas. On 16 July Hitler ordered the preparation of Operation Sea Lion as a potential amphibious and airborne assault on Britain, to follow once the Luftwaffe had air superiority over the UK. In September German preparation of converted barges was disrupted by RAF Bomber Command night raids, and the Luftwaffe failure to overwhelm the RAF forced Hitler to postpone and eventually cancel Operation Sea Lion.

Nazi Germany was unable to sustain daylight raids, but their continued night bombing operations on Britain became known as the Blitz. While the German strategic bombing offensive intensified with the night attacks on London and other cities, it largely failed to disrupt the British war effort. The failure to destroy Britain's air defences to force an armistice (or even outright surrender) is considered to be the first major defeat of Nazi Germany in World War II, and a crucial turning point in the conflict. With the Royal Air Force having successfully resisted the Luftwaffe's assault, German bombing campaign largely ended in May 1940.

The War turns global (1940–41)

Axis attack on the USSR (1940–41)

Invasion of Greece (1940)

Campaign in North Africa (1940–41)

War breaks out in the Pacific (1941)

Entry of the United States

Axis advance stalls (1941–42)

Eastern front (1941–42)

Pacific (1941–42)

North Africa (1941–42)

Allies gain momentum (1943–44)

Eastern front (1943–44)

Pacific (1943–44)

Italy (1943–44)

Axis collapse, Allied victory (1944–45)

Invasion of Normandy and Liberation of France (1944)

German capitulation (1945)

On 16 December 1944, Germany made a last attempt on the Western Front by using most of its remaining reserves to launch a massive counter-offensive in the Ardennes to split the Western Allies, encircle large portions of Western Allied troops and capture their primary supply port at Antwerp to prompt a political settlement. By January, the offensive had been repulsed with no strategic objectives fulfilled. In Italy, the Western Allies remained stalemated at the German defensive line. In mid-January 1945, the Soviets attacked in Poland, pushing from the Vistula to the Oder river in Germany, and overran East Prussia. On 17 January 1945 – after the beginning of the Vistula–Oder Offensive of the Red Army – Soviet troops entered the ruins of Warsaw, and liberated Warsaw's suburbs from German occupation. A successful coup d'état led by Władysław Sikorski removed Rydz-Śmigły from power, and Poland initiated armistice with the Soviet Union on 19 January. While members of the anti-Soviet Polish government and some Polish formations escaped — for a time — with the Germans, an armistice was signed on 28 January, as the Communist-dominated Polish Committee of National Liberation led by Bolesław Bierut was installed by the Soviets. Shortly afterward, on 4 February, Soviet, British and US leaders met for the Yalta Conference. They agreed on the occupation of post-war Germany, and on when the Soviet Union would join the war against Japan.

In February, the Soviets entered Silesia and Pomerania, while Western Allies entered western Germany and closed to the Rhine river. By March, the Western Allies crossed the Rhine north and south of the Ruhr, encircling the German Army Group B. In early March, in an attempt to protect its last oil reserves in Hungary and to retake Budapest, Germany launched its last major offensive against Soviet troops near Lake Balaton. In two weeks, the offensive had been repulsed, the Soviets advanced to Vienna, and captured the city. In early April, Soviet troops captured Königsberg, while the Western Allies finally pushed forward in Italy and swept across western Germany capturing Hamburg and Nuremberg. American and Soviet forces met at the Elbe river on 25 April, leaving several unoccupied pockets in southern Germany and around Berlin.

Soviet and Polish forces stormed and captured Berlin in late April. In Italy, German forces surrendered on 29 April. On 30 April, the Reichstag was captured, signalling the military defeat of Nazi Germany. The Berlin garrison surrendered on 2 May.

Several changes in leadership occurred during this period. On 12 April, President Roosevelt died and was succeeded by Harry S. Truman. Benito Mussolini was killed by Italian partisans on 28 April. Two days later, Hitler committed suicide in besieged Berlin, and he was succeeded by ___________. Total and unconditional surrender in Europe was signed on 7 and 8 May, to be effective by the end of 8 May.

Japan's surrender (1945)

In the Pacific theatre, American forces accompanied by the forces of the Philippine Commonwealth advanced in the Philippines, clearing Leyte by the end of April 1945. They landed on Luzon in January 1945 and recaptured Manila in March following a battle which reduced the city to ruins. Fighting continued on Luzon, Mindanao, and other islands of the Philippines until the end of the war. Meanwhile, the United States Army Air Forces (USAAF) were destroying strategic and populated cities and towns in Japan in an effort to destroy Japanese war industry and civilian morale. On the night of 9–10 March, USAAF B-29 bombers struck Tokyo with thousands of incendiary bombs, which killed 100,000 civilians and destroyed 16 square miles (41 km2) within a few hours. Over the next five months, the USAAF firebombed a total of 67 Japanese cities, killing 393,000 civilians and destroying 65% of built-up areas.

In May 1945, Australian troops landed in Borneo, overrunning the oilfields there. British, American, and Chinese forces defeated the Japanese in northern Burma in March, and the British pushed on to reach Rangoon by 3 May. Chinese forces started to counterattack in Battle of West Hunan that occurred between 6 April and 7 June 1945. American naval and amphibious forces also moved toward Japan, taking Iwo Jima by March, and Okinawa by the end of June. At the same time, American submarines cut off Japanese imports, drastically reducing Japan's ability to supply its overseas forces.

On 11 July, Allied leaders met in Potsdam, Germany. They confirmed earlier agreements about Germany, and reiterated the demand for unconditional surrender of all Japanese forces by Japan, specifically stating that "the alternative for Japan is prompt and utter destruction". During this conference, the United Kingdom held its general election, and Clement Attlee replaced Churchill as Prime Minister.

The Allies called for unconditional Japanese surrender in the Potsdam Declaration of 27 July, but the Japanese government rejected the call. On 6 August 1945 the Soviets, pursuant to the Yalta agreement, invaded Japanese-held Manchuria as well as Vladivostok and the territories captured by Japan in 1940. They quickly defeated the Kwantung Army, which was the largest Japanese fighting force, and liberated Vladivostok on 12 August. The Red Army also captured Sakhalin Island and the Kuril Islands.

On the 6 and 9 August the USAAF dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki. The Allies justified the atomic bombings as a military necessity to avoid invading the Japanese home islands (Operation Downfall) which would cost the lives of between 250,000 and 500,000 Allied servicemen and millions of Japanese troops and civilians. Between the two bombings, On 15 August 1945, Japan surrendered, with the surrender documents finally signed at Tokyo Bay on the deck of the American battleship USS Missouri on 2 September 1945, ending the war.

See also

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