World War II

World War II: Causes, Leaders, Turning Points, and Casualties

• World War II began on September 1, 1939, when Germany invaded Poland, leading to declarations of war by Great Britain and France.
• The main combatants were the Axis powers (Germany, Italy, and Japan) and the Allies (France, Great Britain, the United States, the Soviet Union, and China).
• The war in the Pacific turned against Japan during the Battle of Midway and the Battle of Guadalcanal, while the tide of the war in Europe shifted with the Soviet victory at the Battle of Stalingrad.
• The American "island hopping" campaign and the firebombings of Japanese cities, followed by the atomic bombings of Hiroshima and Nagasaki, led to Japan's surrender and the end of the war.
• Estimates of the total number of people killed during World War II range from 35,000,000 to 60,000,000, with the Soviet Union and China suffering the most total casualties.
• The German-Soviet Nonaggression Pact in Moscow, signed on August 23–24, 1939, paved the way for Hitler's invasion of Poland and the beginning of World War II.
• 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 neighbor.
• Secret negotiations led to the signing of the German-Soviet Nonaggression Pact, with a secret protocol dividing Poland between Germany and the Soviet Union.
• Hitler postponed the start of hostilities for a few days after news of the signing of a formal treaty of mutual assistance between Great Britain and Poland.
• Hitler gave orders for the invasion to start on August 26, 1939, and the invasion began as ordered on August 31, leading to declarations of war by Great Britain and France.
• World War II resulted in the extension of the Soviet Union's power to nations of eastern Europe, enabled a communist movement to eventually achieve power in China, and marked the decisive shift of power in the world toward the United States and the Soviet Union.
• World War II was one of the great watersheds of 20th-century geopolitical history, resulting in the largest and bloodiest conflict in history, with long-lasting effects on the world order.