papigrande:

World War II, or the Second World War^[1] (often abbreviated as WWII or WW2), was a global military conflictlasting from 1939 to 1945, which involved most of the world’s nations, including all of the great powers, organised into two opposing military alliances: the Allies and the Axis. It was the most widespread war in history, with more than 100 million military personnel mobilised. In a state of “total war,” the major participants placed their entire economic, industrial, and scientific capabilities at the service of the war effort, erasing the distinction between civilian and military resources. Marked by significant action against civilians, including the Holocaust and the only use of nuclear weapons in warfare, it was the deadliest conflict in human history,^[2] that resulted in 50 million to over 70 million fatalities.

The war is generally accepted to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and most of the countries of the British Empire andCommonwealth. Germany set out to establish a large German empire in Europe. During 1939 to early 1941, in a series of successful military campaigns and political treaties, Germany conquered or politically subdued most of continental Europe apart from the Soviet Union. Britain and the Commonwealth remained the only major force continuing the fight against the Axis in the Mediterranean and in extensive naval warfare. In June 1941, the European Axis launched an invasion of the Soviet Union, giving a start to the largest land theatre of war in history, which, from this moment on, was tying down the major part of the Axis military power. In December 1941, Japan, which had already been at war with China since 1937,^[3] and which aimed to establish a dominance over East Asia andSoutheast Asia, attacked the United States and European possessions in the Pacific Ocean, quickly conquering a significant part of the region.

The Axis advance was stopped in 1942 after the defeat of Japan in a series of naval battles and after devastating defeats of European Axis troops in the Mediterranean and at Stalingrad. In 1943, with a series of German defeats inEastern Europe, the Allied invasion of Italy and American victories in the Pacific the Axis had lost strategic initiative and passed to strategic retreat on all fronts.

In 1944, the Western Allies invaded France, whereas the Soviet Union regained all territorial losses and invaded the territory of Germany and its allies. The war in Europe ended with the capture of Berlin by Soviet troops and subsequent German unconditional surrender on 8 May 1945. By that time, the Japanese Navy was defeated by the United States, and invasion of the Japanese Archipelago (“Home Islands”) became imminent.

The war ended with the total victory of the Allies over Germany and Japan in 1945. World War II left the political alignment and social structure of the world significantly altered. While the United Nations (UN) was established to foster international cooperation and prevent future conflicts (such as World War III), the Soviet Union and the United States emerged as rival superpowers, setting the stage for the Cold War, which would last for the next 46 years. Meanwhile, the influence of European great powers started to decline, while the decolonization of Asia and of Africabegan. Most countries whose industries had been badly damaged began moving toward economic recovery and across the world political integration emerged in an effort to peacefully stabilise after-war relations.

Chronology

See also: Timeline of World War II

The start of the war is generally held to be 1 September 1939, beginning with the German invasion of Poland; Britain and France declared war on Germany two days later. Other dates for the beginning of war include the Japanese invasion of Manchuria on 13 September 1931;^[4] the start of the Second Sino-Japanese War on 7 July 1937;^[5][6].

Others follow A. J. P. Taylor, who held that there was a simultaneous Sino-Japanese War in East Asia, and a Second European War in Europe and her colonies. The two wars merged in 1941, becoming a single global conflict, at which point the war continued until 1945. This article uses the conventional dating.^[7]

The exact date of the war’s end is not universally agreed upon. It has been suggested that the war ended at the armistice of 14 August 1945 (V-J Day), rather than the formal surrender of Japan (2 September 1945); in some European histories, it ended on V-E Day (8 May 1945). The Treaty of Peace with Japan was not signed until 1951.^[8]

Background

Main article: Causes of World War II

World War I radically altered the diplomatic and political situations in Eurasia and Africa with the defeat of the Central Powers, including Austria-Hungary, Germany, and the Ottoman Empire; and the 1917 Bolshevik seizure of power inRussia. Meanwhile, the success of the Allied Entente powers including the United Kingdom, France, the United States, Italy, Serbia, and Romania, and the creation of new states from the collapse of Austria-Hungary and theRussian Empire, resulted in a major shift in the balance of power from central and eastern Europe to the Atlantic littoral.^{[citation needed]} In the aftermath of the war, major unrest in Europe rose, especially irredentist and revanchistnationalism and class conflict. Irredentism and revanchism were strong in Germany because she was forced to accept significant territorial, colonial, and financial losses as part of 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, massive reparations were imposed, and limits were placed on the size and capability of Germany’s armed forces.^[9] Meanwhile, the Russian Civil War had led to the creation of the Soviet Union. After Lenin’s death in 1924, Joseph Stalin seized power in the USSR and repudiated the New Economic Policy favouring the Five Year Plans instead.^[10]

In the interwar period, domestic civil conflict occurred in Germany involving nationalists and reactionaries versus communists and moderate democratic political parties. A similar scenario occurred in Italy. Although Italy as an Entente ally made some territorial gains, Italian nationalists were angered that the terms of the Treaty of Londonupon which Italy had agreed to wage war on the Central Powers, were not fulfilled with the peace settlement. From 1922 to 1925, the Italian Fascist movement led by Benito Mussolini seized power in Italy with a nationalist, totalitarian, and class collaborationist agenda that abolished representative democracy, repressed political forces supporting class conflict or liberalism, and pursued an aggressive foreign policy aimed at forcefully forging Italy as a world power, and promising to create a “New Roman Empire.”^[11] In Germany, the Nazi Party led by Adolf Hitlerpursued establishing such a fascist government in Germany. With the onset of the Great Depression, Nazi support rose and, in 1933, Hitler was appointed Chancellor of Germany, and in the aftermath of the Reichstag fire, Hitler created a totalitarian single-party state led by the Nazis.^[12]

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.^[13] In 1931, an increasingly militaristic Japanese Empire, which had long sought influence in China^[14] as the first step of its right to rule Asia, used the Mukden Incident as justification to invade Manchuria and established the puppet state of Manchukuo.^[15] Too weak to resist Japan, China appealed to theLeague 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 minor conflicts, in Shanghai, Rehe and Hebei, until signing the Tanggu Truce in 1933. Thereafter, Chinese volunteer forces continued the resistance to Japanese aggression inManchuria, and Chahar and Suiyuan.^[16]