World War II was a war fought on almost every continent in the world from 1939 to 1945. Most of the world's countries, including all of the great powers, fought as part of two alliances: the Allies and the Axis.
Overview of the war.
The start of the war was the invasion of Poland on September 1, 1939, but some sources count the Japanese invasion of China on July 7, 1937, as the actual start of the war. The United States reacted to the Japanese invasion of China by placing an embargo on Japan. France & United Kingdom to the German invasion of Poland by declaring war on Germany. Germany expanded its territory and space greatly in Europe. By 1941, most of Europe was under German control, while only Britain remained fighting against the Axis. In June 1941, the Axis Powers invaded the Soviet Union, starting the largest war in history. This harmed the Axis military power. In December 1941, Japan attacked Western colonies in the Pacific.