It began in 1939 as a European conflict between Germany and an Anglo-French coalition, but eventually included most of the nations of the world. It ended in 1945 as the most destructive war in human history, leaving a new world order dominated by the U.S. and the USSR.
World War II was the mightiest struggle humankind has ever seen. It killed more people, cost more money, damaged more property, affected more people, and caused more far-reaching changes in nearly every country than any other war in history. The number of people killed, wounded, or missing between September 1939 and September 1945 can never be calculated, but it is estimated that more than 55 million people perished.
More than 50 countries took part in the war, and the whole world felt its effects. Men fought in almost every part of the world, on every continent except Antarctica. Chief battlegrounds included Asia, Europe, North Africa, the Atlantic and Pacific oceans, and the Mediterranean Sea.
Attack on Pearl HarborBecause of Japanese actions in French Indochina and China, the United States imposed numerous sanctions, including an oil and scrap metal embargo. The oil embargo threatened to grind the Japanese military machine to a halt. Fearing a shortage of resources, and that war with the United States was inevitable, the Japanese decided to take action against the United States Pacific Fleet stationed at Pearl Harbor. President Roosevelt had months earlier transferred the American fleet there from San Diego in order to present a deterrent to any possible Japanese attack. Shortly after negotiations in Washington broke down, the Japanese launched a full scale surprise attack at Pearl Harbor on the morning of December 7, 1941. While the attack succeeded in sinking and damaging many battleships, the American aircraft carriers were not present, preserving American force projection capabilities.
Hiroshima and NagasakiAs victory for the United States slowly approached, casualties mounted. A fear in the American high command was that an invasion of mainland Japan would lead to enormous losses on the part of the Allies, as casualty estimates for the planned Operation Downfall demonstrate. President Harry Truman gave the order to drop the first atomic bomb on Hiroshima on August 6, 1945, hoping that the destruction of the city would break Japanese resolve and end the war. A second bomb was dropped on Nagasaki on August 9, after it appeared that the Japanese high command was not planning to surrender. Approximately 140,000 people died in Hiroshima from the bomb and its aftereffects by the end of 1945, and approximately 74,000 in Nagasaki, in both cases mostly civilians.
August 15, 1945, or V-J Day, marked the end of the United States' war with the Empire of Japan. Since Japan was the last remaining Axis Power, V-J Day also marked the end of World War II.
