The start of WWII

Although Japan was already at war with China, the global conflict that came to be known as World War II began when Nazi Germany invaded Poland on September 1, 1939, provoking declarations of war from Britain and France. The Soviet Union then invaded Poland two weeks later, dividing Europe in collaboration with the Nazis, though their alliance was short-lived. Following the German invasion of the Soviet Union in 1941, the Soviets joined the allies and played a key role in Germany's defeat four years later. Here is a collection of related articles.