World War II was the most extensive and costly armed conflict in the history of the world, involving the great majority of the world's nations, being fought simultaneously in several major theatres, and costing approximately 55.5 million lives. The war was fought between two groups of powers: the alliance of the British Commonwealth, United States, Soviet Union, China, and the governments-in-exile of France Poland and other occupied European countries—collectively known as the Allies; and the alliance of Germany, Italy, and Japan—collectively known as the Axis.
The German invasion of Poland on 1 September 1939 is the most common date in the West for the start of World War II. Others cite the Japanese invasion of China in 1937 as the war's beginning, or even the 1931 Japanese incursion into Manchuria. The war in Europe ended with the surrender of Germany on 8 May 1945, but continued in Asia and the Pacific until September 2 1945, when Japan surrendered.
The war was significant in that it was the first war in which air power was a significant factor. Indeed, the first combat operation in World War II was a German bombing attack against Poland, while the last combat operation was a thousand-aircraft bombing attack on Japan, on 14 August 1945. The war also saw the re-emergence of the United States from its isolationism, the destruction and rebuilding of Germany and Japan into major industrial powers, the advent of the atomic bomb, and the emergence of the United States and the Soviet Union as global superpowers. The war also directly led to the United Nations, which was founded by the victorious Allies in order to prevent such a large and destructive conflict from ever happening again.
The war caused more civilian casualties than any war in history. This was partly due to its unprecedented scale, the first uses of mass aerial bombings against civilian populations (a policy initiated by the German Luftwaffe against Poland, and later used more extensively against German cities by the Allies), and the first application of industrial age technology to enable the mass killing of unwanted civilians in extermination camps. In total, World War II caused the deaths of about two percent of the population of the world. (For details, see the list of World War II casualties by country.)
Main article: Causes of World War II
The Second World War came about for a variety of reasons. Some of the most commonly mentioned causes include the aggressive rise of totalitarian ideologies, and, from a narrower perspective, war reparations demanded of Germany after World War I coupled with the effects of the Great Depression and the lack of raw materials in Japan.
Prelude to War
Main article: Events preceding World War II in Europe
Resentment of the victorious powers' treatment of the Weimar Republic in the aftermath of World War I, and economic difficulties caused by war reparations and the Great Depression, allowed Adolf Hitler's extreme nationalist NSDAP movement to come to power in Germany. Due to the fragile political situation, Hitler could assume emergency power and virtually total control of the country. Defying post-World War I treaties he redeveloped the German military by means of the democratic constitution that then was put aside. He remilitarized the border zone next to France, enforced the re-unification with Austria in the so-called Anschluss, and with Franco-British approval he annexed parts of Czechoslovakia.
In 1922 Benito Mussolini and the Fascist party had risen to power in Italy. Mussolini's Italian fascists shared some ideological goals with the German National socialists or Nazis and although Mussolini distrusted Hitler, the two countries formed an agreement that became known as the "Rome-Berlin Axis" in 1936.
In 1939, Hitler laid claim to parts of Poland and concluded the Molotov-Ribbentrop Pact with the Soviet Union in response to Britain's and France's supportive defense alliance with Poland, of March 1939. The German Wehrmacht then invaded Poland on September 1, and on 3 September, 1939, Britain and France declared war on Germany. The Polish government collapsed, with President Ignacy Moscicki fleeing into exile on the 18th. Within weeks the Soviet Red Army also invaded Poland, and hostilities ended with French and British troops giving no assistance to the Poles.
The period from the conclusion of the invasion of Poland in October 1939, till the German invasion of Benelux and France in May 1940, became known as the Phony War. The German and Soviet forces were moved from the attack on Poland. The Red Army concentrated on the Baltic countries and on Finland, where the Winter War came in focus of the world's interest in absence of other hostilities. Meanwhile, the Wehrmacht moved to the north and invaded Denmark and Norway in Operation Weserübung. France mobilized and manned its heavily defended border against the Rhine; and the British sent a large expeditionary force to France. Apart from a brief attack by the French across the Rhine there were little hostilities as both sides built up their forces.
In May of 1940 German forces attacked the Low Countries (The Netherlands, Belgium and Luxembourg). The three countries were occupied quickly with all of their governments and monarchs fleeing to London, except for the Belgian king Leopold III who stayed in his country. France was then promptly invaded. The Germans' Blitzkrieg tactics succeeded in defeating the French and British armies in France. The British Expeditionary Force (BEF) evacuated Dunkirk in Operation Dynamo, leaving their heavy equipment behind, and the French government made a peace, which left the Germans in control of the North and the Vichy government in charge of the South.
Luftwaffe was unable to defeat the Royal Air Force in the Battle of Britain and gain the air superiority needed to invade Britain. Instead they began a strategic bombing campaign which the British called the Blitz, and to blockade Britain into submission in the Battle of the Atlantic. Britain failed to succumb to either.
In June 1941 Germany attacked the Soviet Union, with whom they had a non-aggression pact, in Operation Barbarossa, starting what is known in Russia as the Great Patriotic War (ru: Великая Отечественная Война, Velikaya Otechestvennaya Voyna). The Russians were caught largely by surprise and the Wehrmacht initially conquered vast areas of territory, and captured hundreds of thousands of troops. The Soviets withdrew, and managed to move most of their heavy industry away from the front line and re-establish it in more remote areas. Tenacious, sacrificial defense prevented the Germans from capturing Moscow (Hero City) by the time winter set in (see Battle of Moscow). Hitler, expecting the campaign to be over in a few months, had not equipped their armies for winter fighting. Five days after the Soviets launched their counter attack, on December 11, 1941, Germany declared war on the United States following the Attack on Pearl Harbor by Japan - see Asian Theatre.
In spring the German army made further attacks in the Soviet Union, but appeared to be unable to choose between a direct attack on Moscow and the capture of the Caucasian oilfields. Moscow was again spared, and at the end of 1942 the Soviets succeeded in smashing the Axis' front lines in the south, and surrounding the German 6th Army in the Battle of Stalingrad (Hero City). In February 1943 the paltry remnant of the 300,000 man army surrendered. This blunder could have been avoided had Hitler taken Stalingrad when it was empty of Soviet troops; however, he mistakenly believed it was too well defended, setting the stage for the defeat of the 6th Army. In the spring the Wehrmacht was able to restore the front line and make a successful riposte in the Second Battle of Kharkov, but their offensive at the massive Battle of Kursk (July 1943) was so unsuccessful that the Red Army were able to counterattack and regain the ground previously lost. From that time forward the Soviet Union had the initiative in the East. By the early 1944 Red Army reached border of Poland and ended the Siege of Leningrad.
The German disaster at Stalingrad was promptly followed by a disaster of similar importance in Tunisia (see African theatre below), resulting in the loss of the last Axis foothold in North Africa and the capture of a quarter of a million German and Italian POWs (May 1943). Thereafter the Allies used North Africa as a springboard for the invasion of Sicily (July 1943) and mainland Italy (September 1943), which Winston Churchill described as "the soft underbelly of Europe". Italy surrendered, but German troops moved to disarm the Italians and set about defending the country on their own. They established a series of tough defensive lines in mountainous country that was ideally suited to defense, and progress by the Allies was slow.
On June 9 Soviet Union began offensive on Karelian Isthmus forcing German co-belligerent Finland out of war. On June 22 Soviets began Operation Bagration; 2.5 million men and 6,000 tank attack along 1,000 km front, destroying completely German 500,000 men Army Group Centre and taking 350,000 prisoners. Romania surrendered in August and Bulgaria on September. Germans withdrew from Balkans and managed to hold their position in Hungary until February 1945.
After a desperate counteroffensive by the German army in the Ardennes during the Battle of the Bulge in December 1944, the Allies entered Germany in 1945. By now the Soviets had reached the Eastern borders of the German Reich, and her fate was sealed. Red Army captured Vienna April 14 and the final assault on Berlin began on April 16. As the Russians surrounded Berlin, Hitler and his staff moved into the bunker underneath the Chancellery. There, on 30 April 1945, Adolf Hitler committed suicide as Russian shells exploded in the Chancellery garden above. It was twelve years and three months since he had become dictator of Germany. He had appointed Admiral Karl Dönitz President of Germany, but one week later the German armed forces surrendered unconditionally on 8 May 1945.
The Pacific War
Main article: Pacific War
The weakening of China, partly through the actions of British colonialism, and the rapid modernization of Japan in the late 19th century were perhaps the first precursors to the Pacific theatre of the war. Japan modernized its military and went to war with China in 1894, winning handily. Western leaders were surprised at the strength shown by the Japanese. Russia, France and Germany united to force Japan to make land concessions to China. In 1904 Russia and Japan would face off in a war in which Japan is victorious. For the first time, a non-Western country had defeated a European power. The repercussions were felt worldwide as colonies saw that with Western technology, the weapons of the West could be used against the colonizers.
In the First World War, Japan joined the Allied powers, but played only a minor role in fighting German colonial forces in East Asia. At the following Paris Peace Conference of 1919, Japan's proposal of amending a "racial equality clause" to the covenant of the League of Nations was rejected by the United States, Britain and Australia. In 1924 the US Congress passed the Exclusion Act that prohibited further immigration from Japan.
In 1933, Japan withdrew from the League of Nations since she was heavily criticized for her actions in China.
In 1940, Japan occupied French Indochina (Vietnam) upon agreement with the French Vichy government, and joined the Axis powers Germany and Italy. These actions intensified Japan's conflict with the United States and the United Kingdom which reacted with an oil boycott.
The Japanese had already invaded China before World War II started in Europe. U.S. President Roosevelt signed an executive order in May of 1940 allowing U.S. military personnel to resign from the service so that they could participate in a covert operation in China. Hence was born the All Volunteer Group, more commonly known as Chennault's Flying Tigers. With the United States and other countries cutting exports to Japan, Japan decided to bomb Pearl Harbor on 7 December 1941 without warning or declaration of war. Severe damage was done to the American Pacific Fleet, although the aircraft carriers escaped as they were at sea. Japanese forces simultaneously invaded the British possessions of Malaya and Borneo and the American occupied Philippines, with the intention of seizing the oilfields of the Dutch East Indies. The British island fortress of Singapore was captured in what Churchill considered one of the most humiliating British defeats of all time.
In May 1942, a Japanese naval attack on Port Moresby, New Guinea which had it succeeded would have put them within striking range of Australia, was thwarted by the Allied navies in the Battle of the Coral Sea, becoming both the first successful opposition to Japanese plans and the first naval battle fought only between aircraft carriers. A month later the U.S. Navy again prevented the invasion of Midway island, this time destroying four Japanese carriers, which Japanese industry could not replace, and putting the Japanese navy on the defensive.
However, in July the Japanese Army attempted an overland attack on Port Moresby, along the rugged Kokoda Track. Australian reservists, many of them very young and untrained, fought a stubborn rearguard action, until they were relieved by Australian regular troops returning from action in the Middle East.
The Allied leaders had agreed even prior to the American entry to the war that priority should be given to the defeat of Germany. Nonetheless US and Australian forces under General Douglas MacArthur began to attack captured territories, beginning with, against the bitter and determined defense of Japanese troops, Guadalcanal Island. On 7 August 1942 the island was assaulted by United States Marines. In late August and early September, while battle raged on Guadalacanal, Australian forces fought off a Japanese amphibious attack on the eastern tip of New Guinea at Milne Bay, the first conclusive defeat suffered by Japanese land forces. US forces triumphed on Guadalcanal in February 1943.
Exhausted Australian and US forces then strove to retake the occupied parts of New Guinea and the Dutch East Indies, experiencing some of the toughest resistance of the Pacific Theatre. The rest of the Solomon Islands were retaken in 1943, New Britain and New Ireland in 1944. The Philippines were attacked in late 1944 following the Battle of Leyte Gulf.
US and Allied submarines and aircraft also attacked Japanese merchant shipping, depriving Japanese industry of the raw materials she had gone to war to obtain. The effectiveness of this stranglehold increased as the U.S. captured islands closer to the Japanese mainland.
The Nationalist Kuomintang Army under Chiang Kai-shek and the Communist Chinese Army under Mao Zedong both opposed the Japanese occupation of China, but never truly allied against the Japanese. Conflict between Nationalist and Communist forces continued after and, to an extent, even during the war.
Capture by the Allies of islands such as Iwo Jima and Okinawa close to Japan brought the homeland within range of naval and air attacks, Tokyo was firebombed and later an atomic bomb, the "Little Boy", was dropped from the B-29 "Enola Gay" and destroyed Hiroshima. On 8 August 1945 the Soviet Union declared war on Japan, attacking her possessions in Manchuria. On August 9, in Nagasaki, another atom bomb, "Fat Man" was dropped by the B-29 "Bock's Car". The Japanese surrendered on 14 August 1945, signing official surrender papers on 2 September 1945 aboard the USS Missouri in Tokyo Bay.
African and Middle Eastern Theatre
The North African Campaign began in 1940, when small British forces in Egypt turned back an Italian advance from Libya. This advance was stopped in 1941 when German forces under Erwin Rommel landed in Libya. In addition, in June 1941 the Australian Army and allied forces invaded Syria and Lebanon, capturing Damascus on 17 June. Rommel's Afrika Korps advanced rapidly eastward, laying siege to the vital seaport of Tobruk. The Australian and British troops in the city resisted all until relieved, but a renewed Axis offensive captured the city and drove the Eighth Army back to a line at El Alamein.
The First Battle of El Alamein took place between July 1 and July 27, 1942. German forces had advanced to the last defensible point before Alexandria and the Suez Canal. However they had outrun their supplies, and a British and Commonwealth defense stopped their thrusts. The Second Battle of El Alamein occurred between October 23 and November 3, 1942 after Bernard Montgomery had replaced Claude Auchinleck as commander of the Eighth Army. Commonwealth forces took the offensive and destroyed the Afrika Korps. Rommel was pushed back, and this time did not stop falling back until Tunisia.
To complement this victory, on 8 November, 1942, American and British troops landed in Morocco and Algeria in Operation Torch. The local forces of Vichy France put up limited resistance before joining the Allied cause. Ultimately German and Italian forces were caught in the pincers of a twin advance from Algeria and Libya. Advancing from both the east and west, the Allies completely pushed the Wehrmacht out of Africa and on May 13, 1943, the remnants of the Axis forces in North Africa surrendered. 250,000 prisoners were taken; as many as at Stalingrad.
In contrast to World War I, the Western victors in the Second World War did not demand compensation from the defeated nations. On the contrary, a plan created by U. S. Secretary of State George Marshall, the "Economic Recovery Program", better known as the Marshall Plan, called for the U.S. Congress to allocate billions of dollars for the reconstruction of Europe.
The future Warsaw Pact countries did not subscribe to the Marshall Plan. In the Paris Peace Treaty, the Soviet Union's enemies Hungary, Finland and Romania were required to pay war reparations of $300,000,000 each (in 1938 dollars) to the USSR, Hungary and Romania. Italy was required to pay $360,000,000, shared chiefly between Greece, Yugoslavia and the Soviet Union.
In the areas occupied by US troops, capitalist governments were created, in the areas occupied by Soviet troops, communist governments were created. Germany was partitioned into four zones of occupation, with the American, British and French zones grouped as West Germany and the Soviet zone as East Germany. Austria was once again separated from Germany and it, too, was divided into four zones of occupation which eventually re-united and became the state of Austria. The Cold War had begun, and soon NATO and the Warsaw Pact would form.
The repatriation, pursuant to the terms of the Yalta Conference, of two million Russian soldiers who had come under the control of advancing American and British forces, resulted for the most part in their deaths.
The massive research and development involved in the Manhattan Project in order to quickly achieve a working nuclear weapon design greatly impacted the scientific community, among other things creating a network of national laboratories in the United States. In addition, the pressing for numerous calculations for various things like ballistics tables kickstarted the development of electronic computer technology.
In the military sphere, World War II marked the coming of age of airpower, mostly at the expense of warships. While the pendulum continues to swing in this never-ending competition, air powers are now a full partner in any military action. World War II also saw the creation of guided missiles which, like airpower, are now used in virtually every conflict.
The war was the high-water mark for mass armies. While huge armies of low-quality troops would be seen again (during the Korean War and in a number of African conflicts), after this victory the major powers relied upon small highly-trained and well-equipped militaries.
After the war, many high-ranking Germans were prosecuted for war crimes, as well as the mass murder of the Holocaust committed mainly on the area of General Government, in the Nuremberg trials. Similarly Japanese leaders were prosecuted in the Tokyo War Crime Trial. In other countries, notably in Finland, the Allies demanded the political leadership to be prosecuted in "war-responsibility trials" - i.e. not for crimes of war.
The defeat of Japan, and her occupation by American Forces, led to a westernization of Japan that was surely more far-reaching than would otherwise have occurred. Japan approximated more closely to a Western style democracy and, because of her defeat by the USA, set out to imitate the United States. This huge national effort led to the post-war Japanese economic miracle and Japan's rise to become the world's second largest economy.
World War II military history by country
- Military history of Germany during World War II
- Military history of Britain during World War II
- Military history of Italy during World War II
- Battle of Dunkirk "Dynamo"
- Battle of Britain
- Battle of Crete
- Operation Barbarossa
- Battle of Moscow
- Battle of Kursk
- Battle of Stalingrad
- Operation Bagration
- First Battle of El Alamein
- Second Battle of El Alamein
- Battle of Normandy, also known as D-Day or Operation Overlord
- Battle of Tali-Ihantala
- Operation Market Garden (Battle of Arnhem)
- Battle of Monte Cassino
- Battle of Ardennes (1944) (a.k.a. Battle of the Bulge)
- Battle of Hurtgen Forest
- Battle of Berlin
- Battle of Leyte
- Battle of Peleliu
- Battle of Iwo Jima
- Battle of Okinawa
- Battle of Lugou Bridge
- Battle of Tai er zhuang
- Battle of Changsha
- Battle of Hundred Regiments
- Battle of Milne Bay
- Siege of Leningrad
- Siege of Lwów
- Siege of Modlin
- Siege of Novorossiysk
- Siege of Odessa
- Siege of Sevastopol
- Siege of Tobruk
- Siege of Warsaw
- The Battle of the River Plate
- First Battle of Narvik
- Second Battle of Narvik
- Battle of the Atlantic (1940)
- Battle of Cape Matapan
- Battle of Pearl Harbor
- Battle of the Coral Sea
- Battle of Midway
- Battle of Guadalcanal
- Battle of Leyte Gulf
Major bombing campaigns
- Rostock (Heinckel Airplane Construction Plant, Seaport, and City)
- Baedeker raids
- London ("The Blitz" and the V1 and V2 campaigns)
- Bombing of Stalingrad 23 August 1942
- Helsinki February 1944, was mostly ineffective due to air defense and deception.
- Tallinn February - March 1944. Bombed by Soviet ADD. Large-scale damage.
- Narva March 1944. Evacuated town was destroyed by Soviet ADD.
See also Strategic bombing survey for the overall impact of the bombing.
- Occupation of Denmark
- German children 1933-1945
- Nazi children in the times of peace
- Gold Star Mothers Club for those mothers who lost their children, KIA
Production and logistics
The Axis lost, at least partly because the Allies, after the USA's and the Soviet Union's entrance into the war, had greater productive resources, and were able to turn these resources into greater numbers of soldiers and weapons than the Axis.
- American tank production during World War II
- German tank production during World War II
- Soviet tank production during World War II
- WW2 aircraft production
- US weapon production (1942-1945)
Common military awards
- Hero of the Soviet Union
- Order of Lenin
- Order of Suvorov
- Order of the October Revolution
- Order of the Red Banner
- Order of Victory
In Soviet Union orders and medals were also awarded to cities and military divisions.
- Medal of Honor
- Silver Star
- Bronze Star Medal
- Distinguished Flying Cross
- Air Medal
- World War II Victory Medal
- Asiatic-Pacific Campaign Medal
- European-African-Middle Eastern Campaign Medal
- American Campaign Medal
- Timeline of the Second World War
- Axis Powers
- Generalplan Ost
- British Women's Land Army
- Polish contribution to World War II
- Free French Forces
- Deutsches Afrika Korps
- Potsdam Agreement
- Sino-Japanese War (1937-1945)
- The Dambusters raid
- Devil's Brigade
- Operation Shingle
- Persecutions of Nazi collaborators
- Special Operations Executive
- Female roles in the world wars
- List of World War II Theatres and Campaigns
- List of countries involved in World War II
- List of World War II casualties by country
- List of people associated with World War II
- List of World War II Veterans
- List of equipment used in World War II
- List of World War II aces by country
- Glossary of German WWII military terms
- WW2 People's War - A project by the BBC to gather the stories of ordinary people from World War II
- World War II, Wars And Battles
- BBC History of WW2
- Using Historical Statistics To Teach about World War II. ERIC Digest.
- World War II in the Curriculum
- World War II Memorial Pictures
- Directory of Online World War II Indexes & Records
- World War 2 Online Newspaper Archives
- Winston Churchill, The Second World War, 6 vols. (1948-1953)
- Martin Gilbert, Second World War, Phoenix, 1995. ISBN 1857993462
- John Keegan, The Second World War (1989)
- B.H. Liddell Hart, History of the Second World War (1970)
- Williamson Murray and Allan R. Millett, A War to Be Won: Fighting the Second World War (2000) ISBN 067400163X
- Richard Overy, Why the Allies Won, Pimlico, 1995. ISBN 0712674535
- Gerhard L. Weinberg, A World at Arms: A Global History of World War II (1994) ISBN 0521443172