SUMMARY AND OVERVIEW OF THE SECOND WORLD WAR
Coming just two decades after the last great global conflict, the Second World War was the most widespread and deadliest war in history, involving more than 30 countries and resulting in more than 50 million military and civilian deaths (with some estimates as high as 85 million dead). Sparked by Adolf Hitler’s invasion of Poland in 1939, the war would drag on for six deadly years until the final Allied defeat of both Nazi Germany and Japan in 1945.
World War II (WWII or WW2), also known as the Second World War (after the recent Great War), was a global war that lasted from 1939 to 1945, though related conflicts began earlier. 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 over 30 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 (during which approximately 11 million people were killed) and the strategic bombing of industrial and population centres (during which approximately one million people were killed, including the use of two nuclear weapons in combat), it resulted in an estimated 50 million to 85 million fatalities. These made World War II the deadliest conflict in human history.
The outbreak of war
By the early part of 1939 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. Secret negotiations led on August 23–24 to the signing of the German-Soviet Nonaggression Pact in Moscow. In a secret protocol of this pact, the Germans and the Soviets agreed that Poland should be divided between them, with the western third of the country going to Germany and the eastern two-thirds being taken over by the U.S.S.R. 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 26. 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 determined, however, to ignore the diplomatic efforts of the western powers to restrain him. Finally, at 12:40 pm on August 31, 1939, Hitler ordered hostilities against Poland to start at 4:45 the next morning. The invasion began as ordered. In response, Great Britain and France declared war on Germany on September 3, at 11:00 am and at 5:00 pm, respectively. World War II had begun.
Casualties in World War II
The most destructive war in all of history, its exact cost in human lives is unknown, but casualties in World War II may have totaled 50 million service personnel and civilians killed. Nations suffering the highest losses, military and civilian, in descending order, are:
World War II deaths
Estimates for the total casualties of the war vary, because many deaths went unrecorded. Most suggest that some 75 million people died in the war, including about 20 million military personnel and 40 million civilians. Many of the civilians died because of deliberate genocide, massacres, mass-bombing, disease, and starvation.
The Soviet Union lost around 27 million people during the war, including 8.7 million military and 19 million civilian deaths. The largest portion of military dead were 5.7 million ethnic Russians, followed by 1.3 million ethnic Ukrainians. A quarter of the people in the Soviet Union were wounded or killed. Germany sustained 5.3 million military losses, mostly on the Eastern Front and during the final battles in Germany.
Of the total deaths in World War II, approximately 85 percent—mostly Soviet and Chinese—were on the Allied side and 15 percent on the Axis side. Many of these deaths were caused by war crimes committed by German and Japanese forces in occupied territories. An estimated 11 to 17 million civilians died as a direct or indirect result of Nazi ideological policies, including the systematic genocide of around 6 million Jews during the Holocaust, along with a further 5 to 6 million ethnic Poles and other Slavs (including Ukrainians and Belarusians)—Roma, homosexuals, and other ethnic and minority groups. Hundreds of thousands (varying estimates) of ethnic Serbs, along with gypsies and Jews, were murdered by the Axis-aligned Croatian Ustaše in Yugoslavia, with retribution-related killings just after the war ended.
The Second World War was arguably the most significant period of the 20th century. It brought about major leaps in technology and laid the groundwork that permitted post-war social changes including the end of European colonialism, the civil rights movement in the United States, and the modern women’s rights movement, as well as the programs for exploring outer space. The primary combatants were the Axis nations (Nazi Germany, Facist Italy, Imperial Japan and their smaller allies) and the Allied nations, led by Britain (and its Commonwealth nations), the Union of Soviet Socialist Republics and the United States of America. The Allies were the victors. Two superpowers, the USA and USSR, emerged from World War II to begin a Cold War with each other that would define much of the rest of the century.
The Empire of Japan aimed to dominate Asia and the Pacific and was already at war with the Republic of China in 1937, but the world war is generally said to have begun on 1 September 1939 with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom. 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. Following the Molotov–Ribbentrop Pact, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Poland, Finland, Romania and the Baltic states. For a year starting in late June 1940, the United Kingdom and the British Commonwealth were the only Allied forces continuing the fight against the European Axis powers, with campaigns in North Africa and the Horn of Africa as well as the long-running Battle of the Atlantic. In June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history, which trapped the major part of the Axis’ military forces into a war of attrition. In December 1941, Japan attacked the United States and European territories in the Pacific Ocean, and quickly conquered much of the Western Pacific.