The Second World War was a global war that lasted from 1939 to 1945. It involved many of the world's nations, including all of the great powers, and was ultimately fought between the Axis powers (led by Germany, Japan, and Italy) and the Allied powers (led by the United Kingdom, the Soviet Union, and the United States). The war began with the invasion of Poland by Germany and the Soviet Union, followed by the British and French declaration of war on Germany in September 1939. Over the next six years, the war would see extensive fighting in Europe, Africa, and Asia, as well as the Pacific and Atlantic oceans.
The war saw the rise of powerful military leaders on both sides, such as Adolf Hitler in Germany, Joseph Stalin in the Soviet Union, and Franklin D. Roosevelt in the United States. It also saw the development and use of new and devastating weapons, such as nuclear bombs, long-range missiles, and jet aircraft.
One of the key events of the war was the invasion of the Soviet Union by Germany in 1941, which was met with fierce resistance by the Soviets. This marked a major turning point in the war, as the Soviet Union was able to push the Germans back and eventually liberate much of Eastern Europe.
Meanwhile, in the Pacific, Japan had been expanding its empire and was at war with China. In December 1941, Japan launched a surprise attack on the United States naval base at Pearl Harbor, drawing the US into the war. The US, along with its allies, was able to push back against Japanese forces and eventually drop atomic bombs on the cities of Hiroshima and Nagasaki, bringing about Japan's surrender and effectively ending the war.
The war resulted in the deaths of millions of people, including civilians, and had a profound impact on global politics and society. It also led to the formation of the United Nations and laid the groundwork for the Cold War between the Western powers and the Soviet Union.