World War II was a global military conflict which involved a majority of the world's nations, including all of the great powers, organized into two opposing military alliances: the Allies and the Axis. The war involved the mobilisation of over 100 million military personnel, making it the most widespread war in history. In a state of "total war", the major participants placed their complete economic, industrial, and scientific capabilities at the service of the war effort, erasing the distinction between civilian and military resources. Over seventy million people, the majority of whom were civilians, were killed, making it the deadliest conflict in human history. From the invasion of Poland by Germany on 1 September 1939, to the defeat of Germany and Japan by a relentless tide of aircraft, tanks, ships, and men, the combined Allied effort finally saw the end of war in Europe. Atomic bombs finally ended the war against Japan.
Pre-war (1919 - 31 Aug 1939)
World War I, "The War to End All Wars", was to create many of the conditions that would lead to the outbreak of an even more destructive conflict - World War II. The treaties that ended World War I did not bring worldwide peace. Various nations fought against each other or were torn apart by civil war. The Treaty of Versailles left two dangerous legacies: A bitter, impoverished Germany and an Eastern Europe made up of small, politically-fragmented states. Their aggressiveness and opportunism led to World War II.
After months of diplomatic wrangling and "appeasement" bargaining, war erupted when Germany invaded Poland. Germany's Blitzkrieg offensive heralded a new and dramatic style of modern warfare. Although there was no Allied advance into Germany in Western Europe, fighting flared up on the Eastern Front between the Soviet Union and neighboring Finland. More than fifteen hundred years ago, the Chinese strategist Sun-tzu wrote, "Every battle is won before it is ever fought." It would take 6 years to determine the victor.
The German Army conquered much of Western Europe in 1940 in a series of spectacular Blitzkrieg victories. German armor and aircraft attacked and defeated a succession of Allied armies in Scandinavia, France, and the Low Countries. Germany's defeat in an aerial battle over Britain, however, saved that nation from any invasion. Britain's survival now depended on North American aid. Meanwhile, the war widened, with Italian offensives in Africa and the Balkans.
TThe Allies continued fighting in North Africa, where they now faced General Erwin Rommel's Afrika Korps, and the war in the Balkans intensified with Germany conquering Yugoslavia and Greece. In the Mediterranean and Atlantic, the Allies fought a bitter campaign to defend their vital sea-lanes. The Axis powers' declarations of war on the Soviet Union and the United States proved a critical turning point. Germany undertook a bitter campaign on the Eastern Front, while Japan had to safeguard its conquests in the Pacific.
Japan's territorial conquests appeared to signal its triumph over Europe's colonial powers in the Far East. The United States, however, was now on the offensive and won crucial strategic victories at sea over the Japanese. These had serious repercussions for Japan's ability to sustain its domestic and overseas power. In North Africa and on the Eastern Front, Axis offensives, although initially successful, were halted and then defeated by a series of Allied counterattacks. Control of the sea-lanes continued to be crucial in the war.
Allied successes in Papua New Guinea and the Solomon Islands, together with hard-won British and Chines advances in Burma, forced the Japanese onto the defensive in the Pacific and Far East. Allied forces also triumphed in North Africa and went on to invade Italy, triggering the fall of Mussolini, while in the Soviet Union, the clash of armor at Kursk resulted in a key German defeat.
In the Pacific, Japanese defeats at the Battle of the Philippine Sea and around the Mariana Islands, plus losses in Burma, signaled the growing might of the Allies. In Europe, Axis forces suffered reverses and withdrawals in Italy, France, and on the Eastern Front, as the Allies invaded northern France and Italy. Meanwhile, the Red Army virtually wiped out Army Group Center.
In the final year of the war, Germany and Japan were defeated by a relentless tide of aircraft, tanks, ships, and men. Their cities were devastated by fleets of bombers, their armies were encircled and then annihilated, and their merchant and naval fleets were either sunk or trapped in port. There was no match for the economic might of the United States and the numerical superiority of the Soviet Union. The combined Allied effort finally saw the end of war in Europe. Atomic bombs finally ended the war against Japan.