World war 2
World War II or the Second World War, often
abbreviated as WWII or WW2, was a global war that
lasted from 1939 to 1945. It involved the vast majority of
the world's countries—including all of the great powers
—forming two opposing military alliances: the Allies and
the Axis powers. In a total war directly involving more
than 100 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, enabling the strategic bombing of population
centres and the only two uses of nuclear weapons in
war to this day. World War II was by far the deadliest
conflict in human history; it resulted in 70 to 85 million
fatalities, a majority being civilians. Tens of millions of
people died due to genocides (including the
Holocaust), starvation, massacres, and disease. In the
wake of the Axis defeat, Germany and Japan were
occupied, and war crimes tribunals were
conducted against German and Japanese leaders.
World War II is generally considered to have begun on 1
September 1939, when Nazi Germany, under Adolf
Hitler, invaded Poland. The United
Kingdom and France subsequently declared war on
Germany on 3 September. Under the Molotov–
Ribbentrop Pact of August 1939, Germany and
the Soviet Union had partitioned Poland and marked out
their "spheres of influence"
across Finland, Romania and the Baltic states. From
late 1939 to early 1941, 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). Following the onset of campaigns
in North Africa and East Africa, and the fall of France in
mid-1940, the war continued primarily between the
European Axis powers and the British Empire, with war
in the Balkans, the aerial Battle of Britain, the Blitz of the
UK, and the Battle of the Atlantic. On 22 June 1941,
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.
Japan, which aimed to dominate Asia and the Pacific,
was at war with the Republic of China by 1937. In
December 1941, Japan attacked American and British
territories with near-simultaneous offensives against
Southeast Asia and the Central Pacific, including
an attack on the US fleet at Pearl Harbor which forced
the US to declare war against Japan; the European Axis
powers declared war on the US in solidarity. Japan soon
captured much of the western Pacific, but its advances
were halted in 1942 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 1943—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 1944, the
Western Allies invaded German-occupied France, while
the Soviet Union regained its territorial losses and
turned towards Germany and its allies. During 1944 and
1945, 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 1945. Following the Potsdam Declaration by the
Allies on 26 July 1945 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 1945, 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.
