19391945

1939–1945 marks the period of World War II, a global conflict that involved most of the world’s nations and reshaped international politics. The war began with Germany’s invasion of Poland on September 1, 1939, after which Britain and France declared war on Germany. In the early years, the Axis powers—Germany, Italy, and Japan—expanded aggressively, seizing large parts of Europe, North Africa, and Southeast Asia. Poland was partitioned, and France fell in 1940. The Battle of Britain in 1940 preserved Allied air defense and prevented a German invasion.

In 1941, Germany invaded the Soviet Union and Japan attacked Pearl Harbor, bringing the United States into the conflict. The war thus became a truly global struggle, fought on multiple fronts in Europe, North Africa, the Mediterranean, and the Pacific. Key turning points included the Soviet victory at Stalingrad (1942–43), the Allied victory at El Alamein (1942), and advances in 1943–44 culminating in the Allied invasions of Italy and the D-Day landings in Normandy on June 6, 1944. The war in Europe concluded with Germany’s unconditional surrender on May 8, 1945 (V-E Day).

In the Pacific, Allied campaigns gradually forced Japanese surrender, aided by strategic bombing and the atomic bombings of Hiroshima and Nagasaki in August 1945. Japan’s formal surrender occurred on September 2, 1945, ending World War II. The conflict's aftermath reshaped international politics, leading to the founding of the United Nations, war crimes trials, and significant geopolitical realignments.