What started World War II?
In August Roosevelt met with the British prime minister, Winston Churchill, off the coast of Newfoundland to issue a set of war aims known as the Atlantic Charter. It called for national self-determination, larger economic opportunities, freedom from fear and want, freedom of the seas, and disarmament. World War II in the West () On April 9, , Germany simultaneously invaded Norway and occupied Denmark, and the war began in earnest. On May 10, .
World War IIalso called Second World Warconflict that involved virtually every part of the world ux the years — The war was in many respects a continuation, after an uneasy year hiatusof the disputes left unsettled by World War I.
The 40,—50, deaths incurred in World War II make it the bloodiest conflict, as well as the largest war, how to make your eyes look a different color history. Great Britain and France responded by declaring war on Germany on September 3. The war ghe the U. Roosevelt and Harry S. Truman United States. The tide of the war in Europe shifted with the Soviet victory at the Battle of Stalingrad February More than one million Soviet troops what started world war 2 for the us tens of thousands of civilians died in the defense of the city, but the destruction of two entire German armies marked the beginning of the end of the Third Reich.
The Red Army advanced sarted the east and effectively claimed all the territory under its control for the Soviet sphere. The Allied armies converged on Berlin. Adolf Hitler committed suicide on April 30,and the war in Europe ended on May 8. Hundreds of thousands were killed in firebombings of Japanese cities, and the atomic bombing of Hiroshima and Nagasaki in August knocked Japan out of the war.
An estimated 40, to 50, people died during World War II. Among the Allied powers, the U. AboutAmericans died. Among the Axis powers, there were about 4, German deaths and about 1, Japanese deaths. By the early part of the German dictator Adolf Hitler had become determined to invade and occupy Poland. Poland, for its part, had guarantees of French and British military support should it be attacked by Germany.
Hitler intended to invade Poland anyway, but first he had to neutralize the possibility that the Soviet Union would resist the invasion of its western neighbour. In a secret protocol of what cell organelle transports proteins pact, the Germans and the Soviets agreed that Poland should be divided between them, with the western third of the country wlrld to Germany and the eastern two-thirds being taken over by the U.
Having achieved this cynical agreement, the other provisions of which stupefied Europe even without divulgence of the secret protocol, Hitler thought that Germany could attack Poland with no danger of Soviet or British intervention and gave orders for the invasion to start on August News of the signing, on August 25, of a formal treaty of mutual assistance between Great Britain and Poland to supersede a previous though temporary agreement caused him to postpone the start of hostilities for a few days.
He was still qhat, however, to ignore the diplomatic efforts of the western powers to restrain him. Finally, at pm on August 31,Hitler ordered hostilities against Poland to start at the next morning. The invasion began as ordered. In response, Great Britain wkrld France declared ghe on Germany on September 3, at am and at pmrespectively. World War II had begun.
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The United States at war
In September , German armies invaded Poland and France and Britain declared war on Germany. Britain’s Commonwealth, including Australia, New Zealand and Canada, joined in the war, but the United States and the Soviet Union at first remained neutral. World War II had begun.”. Mar 14, · World War II began in Europe on September 1, , when Germany invaded Poland. Great Britain and France responded by declaring war on Germany on September 3. The war between the U.S.S.R. and Germany began on June 22, , with the German invasion of the Soviet Union. World War II was the biggest and deadliest war in history, involving more than 30 countries. Sparked by the Nazi invasion of Poland, the war dragged on for six bloody years until the Allies.
Mediterranean and Middle East. It involved the vast majority of the world's countries —including all the great powers —forming two opposing military alliances : the Allies and the Axis powers. In a state of total war , directly involving more than million personnel from more than 30 countries, the major participants threw their entire economic, industrial, and scientific capabilities behind the war effort , blurring the distinction between civilian and military resources.
Aircraft played a major role in the conflict, including the strategic bombing of population centres, and, with the development of nuclear weapons , the only two uses of such in war. World War II was the deadliest conflict in human history, resulting in 70 to 85 million fatalities , with more civilians than military personnel killed. Tens of millions of people died due to genocides including the Holocaust , starvation , massacres , and disease. In the wake of the war, Germany and Japan were occupied , and war crimes tribunals were conducted against German and Japanese leaders.
From late to early , in a series of campaigns and treaties , Germany conquered or controlled much of continental Europe , and formed the Axis alliance with Italy and Japan along with other countries later on. On 22 June , Germany led the European Axis powers in an invasion of the Soviet Union , opening the Eastern Front, the largest land theatre of war in history and trapping the Axis powers, crucially the German Wehrmacht , in a war of attrition.
Japan, which aimed to dominate Asia and the Pacific , was at war with the Republic of China by Japan soon captured much of the western Pacific, but its advances were halted in after losing the critical Battle of Midway ; later, Germany and Italy were defeated in North Africa and at Stalingrad in the Soviet Union.
Key setbacks in —including a series of German defeats on the Eastern Front, the Allied invasions of Sicily and the Italian mainland , and Allied offensives in the Pacific—cost the Axis powers their initiative and forced it into strategic retreat on all fronts. In , the Western Allies invaded German-occupied France , while the Soviet Union regained its territorial losses and turned towards Germany and its allies.
During and , Japan suffered reversals in mainland Asia, while the Allies crippled the Japanese Navy and captured key western Pacific islands. The war in Europe concluded with the liberation of German-occupied territories , and the invasion of Germany by the Western Allies and the Soviet Union, culminating in the fall of Berlin to Soviet troops, Hitler's suicide and the German unconditional surrender on 8 May Following the Potsdam Declaration by the Allies on 26 July and the refusal of Japan to surrender on its terms, the United States dropped the first atomic bombs on the Japanese cities of Hiroshima , on 6 August, and Nagasaki , on 9 August.
Faced with an imminent invasion of the Japanese archipelago , the possibility of additional atomic bombings, and the Soviet entry into the war against Japan and its invasion of Manchuria , Japan announced its intention to surrender on 15 August, then signed the surrender document on 2 September , cementing total victory in Asia for the Allies.
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, and 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 the 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 , began as an effort to forestall future hostilities, end pre-war enmities and forge a sense of common identity. The war in Europe is generally considered to have started on 1 September ,   beginning with the German invasion of Poland ; the United Kingdom and France declared war on Germany two days later.
The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July ,   or the earlier Japanese invasion of Manchuria , on 19 September Others follow the British historian A. Taylor , who held that the Sino-Japanese War and war in Europe and its colonies occurred simultaneously, and the two wars merged in This article uses conventional dating.
The exact date of the war's end is also not universally agreed upon. It was generally accepted at the time that the war ended with the armistice of 14 August V-J Day , rather than with the formal surrender of Japan on 2 September , which officially ended the war in Asia.
A peace treaty between Japan and the Allies was signed in World War I had radically altered the political European map, with the defeat of the Central Powers —including Austria-Hungary , Germany , Bulgaria and the Ottoman Empire —and the Bolshevik seizure of power in Russia , which led to the founding of the Soviet Union.
To prevent a future world war, the League of Nations was created during the 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 ,  irredentist and revanchist nationalism emerged in several European states in the same period. These sentiments were especially marked in Germany because of the significant territorial, colonial, and financial losses imposed by the Treaty of Versailles. Under the treaty, Germany lost around 13 percent of its home territory and all its overseas possessions , 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 — , 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 the United Kingdom and France to secure Italian entrance into the war were not fulfilled in the peace settlement.
From to , 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 making Italy a world power , and promising the creation of a " New Roman Empire ".
Adolf Hitler , after an unsuccessful attempt to overthrow the German government in , eventually became the Chancellor of Germany in when Paul Von Hindenburg and the Reichstag appointed him. He abolished democracy, espousing a radical, racially motivated revision of the world order , and soon began a massive rearmament campaign. The situation was aggravated in early 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.
The United Kingdom, France and Italy formed the Stresa Front in April in order to contain Germany, a key step towards military globalisation ; however, that June, 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.
Hitler defied the Versailles and Locarno treaties by remilitarising the Rhineland in March , encountering little opposition due to the policy of appeasement. The Kuomintang KMT party in China launched a unification campaign against regional warlords and nominally unified China in the mids, but was soon embroiled in a civil war against its former Chinese Communist Party allies  and new regional warlords. In , an increasingly militaristic Empire of Japan , which had long sought influence in China  as the first step of what its government saw as the country's right to rule Asia , staged the Mukden Incident as a pretext to invade Manchuria and establish the puppet state of Manchukuo.
China appealed to the League of Nations to stop the Japanese invasion of Manchuria. 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 Thereafter, Chinese volunteer forces continued the resistance to Japanese aggression in Manchuria , and Chahar and Suiyuan.
The war began with the invasion of the Ethiopian Empire also known as Abyssinia by the armed forces of the Kingdom of Italy Regno d'Italia , which was launched from Italian Somaliland and Eritrea. Both Italy and Ethiopia were member nations, but the League did little when the former clearly violated Article X of the League's Covenant.
When civil war broke out in Spain, Hitler and Mussolini lent military support to the Nationalist rebels , led by General Francisco Franco. Italy supported the Nationalists to a greater extent than the Nazis did: altogether Mussolini sent to Spain more than 70, ground troops and 6, aviation personnel, as well as about aircraft.
More than 30, foreign volunteers, known as the International Brigades , also fought against the Nationalists. Both Germany and the Soviet Union used this proxy war as an opportunity to test in combat their most advanced weapons and tactics. The Nationalists won the civil war in April ; Franco, now dictator, remained officially neutral during World War II but generally favoured the Axis. In July , Japan captured the former Chinese imperial capital of Peking after instigating the Marco Polo Bridge Incident , which culminated in the Japanese campaign to invade all of China.
The Japanese continued to push the Chinese forces back, capturing the capital Nanking in December After the fall of Nanking, tens or hundreds of thousands of Chinese civilians and disarmed combatants were murdered by the Japanese. In March , Nationalist Chinese forces won their first major victory at Taierzhuang but then the city of Xuzhou was taken by the Japanese in May.
In the mid-to-late s, Japanese forces in Manchukuo had sporadic border clashes with the Soviet Union and Mongolia. The Japanese doctrine of Hokushin-ron , which emphasised Japan's expansion northward, was favoured by the Imperial Army during this time. With the Japanese defeat at Khalkin Gol in , the ongoing Second Sino-Japanese War  and ally Nazi Germany pursuing neutrality with the Soviets, this policy would prove difficult to maintain.
Japan and the Soviet Union eventually signed a Neutrality Pact in April , and Japan adopted the doctrine of Nanshin-ron , promoted by the Navy, which took its focus southward, eventually leading to its war with the United States and the Western Allies. In Europe, Germany and Italy were becoming more aggressive.
In March , Germany annexed Austria , again provoking little response from other European powers. Soon the United Kingdom and France followed the appeasement policy of British Prime Minister Neville Chamberlain and conceded this territory to Germany in the Munich Agreement , which was made against the wishes of the Czechoslovak government, in exchange for a promise of no further territorial demands.
Although all of Germany's stated demands had been satisfied by the agreement, privately Hitler was furious that British interference had prevented him from seizing all of Czechoslovakia in one operation. In subsequent speeches Hitler attacked British and Jewish "war-mongers" and in January secretly ordered a major build-up of the German navy to challenge British naval supremacy.
In March , Germany invaded the remainder of Czechoslovakia and subsequently split it into the German Protectorate of Bohemia and Moravia and a pro-German client state , the Slovak Republic. Greatly alarmed and with Hitler making further demands on the Free City of Danzig , the United Kingdom and France guaranteed their support for Polish independence ; when Italy conquered Albania in April , the same guarantee was extended to the Kingdoms of Romania and Greece.
The situation reached a general crisis in late August as German troops continued to mobilise against the Polish border. On 23 August, when tripartite negotiations about a military alliance between France, the United Kingdom and Soviet Union stalled,  the Soviet Union signed a non-aggression pact with Germany.
Immediately after that, Hitler ordered the attack to proceed on 26 August, but upon hearing that the United Kingdom had concluded a formal mutual assistance pact with Poland and that Italy would maintain neutrality, he decided to delay it.
In response to British requests for direct negotiations to avoid war, Germany made demands on Poland, which only served as a pretext to worsen relations. On 1 September , Germany invaded Poland after having staged several false flag border incidents as a pretext to initiate the invasion. The alliance provided no direct military support to Poland, outside of a cautious French probe into the Saarland.
On 8 September, German troops reached the suburbs of Warsaw. The Polish counter offensive to the west halted the German advance for several days, but it was outflanked and encircled by the Wehrmacht. Remnants of the Polish army broke through to besieged Warsaw. On 17 September , after signing a cease-fire with Japan , the Soviet Union invaded Eastern Poland  under a pretext that the Polish state had ostensibly ceased to exist.
Despite the military defeat, Poland never surrendered; instead, it formed the Polish government-in-exile and a clandestine state apparatus remained in occupied Poland.
Germany annexed the western and occupied the central part of Poland , and the Soviet Union annexed its eastern part ; small shares of Polish territory were transferred to Lithuania and Slovakia. On 6 October, Hitler made a public peace overture to the United Kingdom and France but said that the future of Poland was to be determined exclusively by Germany and the Soviet Union. The proposal was rejected,  and Hitler ordered an immediate offensive against France,  which was postponed until the spring of due to bad weather.
The Soviet Union forced the Baltic countries —Estonia, Latvia and Lithuania, which were in the Soviet "sphere of influence" under the Molotov-Ribbentrop pact—to sign "mutual assistance pacts" that stipulated stationing Soviet troops in these countries. Soon after, significant Soviet military contingents were moved there. Meanwhile, Nazi-Soviet political rapprochement and economic co-operation   gradually stalled,   and both states began preparations for war.
In April , Germany invaded Denmark and Norway to protect shipments of iron ore from Sweden , which the Allies were attempting to cut off. British discontent over the Norwegian campaign led to the appointment of Winston Churchill as Prime Minister on 10 May On the same day, Germany launched an offensive against France. To circumvent the strong Maginot Line fortifications on the Franco-German border, Germany directed its attack at the neutral nations of Belgium , the Netherlands , and Luxembourg.
The United Kingdom was able to evacuate a significant number of Allied troops from the continent by early June, although abandoning almost all their equipment.
Eight days later France signed an armistice with Germany ; it was divided into German and Italian occupation zones ,  and an unoccupied rump state under the Vichy Regime , which, though officially neutral, was generally aligned with Germany.