the war begins library

The outbreak of World War II pitted the Axis Powers against the allied nations of Europe. Learn about the events surrounding the outbreak of World War II.

Featured Article: Outbreak of World War II

War Begins. In the early hours of Friday, September 1, 1939, the German armies stormed across the Polish frontierwithout a declaration of war. See more »

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Buildup to World War II: January 1931-August 1939

This World War II timeline highlights important dates during January 1931 to August 1939. This time period saw Japan and Italy break away from the League of Nations and the rise of the Nazi Party in Germany. Follow the events of World War II.

Japan Bombs Pearl Harbor: July 1941-December 1941

Japan's bombing of Pearl Harbor was the major event that caused the United States to enter World War II. On December 7, 1941, Japan bombed the harbor, which damaged 300 planes, eight battleships, and killed over 2,000 people. Learn more about the attack.

Outbreak of World War II

War Begins. In the early hours of Friday, September 1, 1939, the German armies stormed across the Polish frontierwithout a declaration of war.

Start of World War II: September 1939-March 1940

This World War II timeline highlights important dates from September 1939 to April 1940. This time period saw the official start to World War II on September 1, 1939 when Germany invaded Poland. Follow the events of World War II and the German invasion.