World War II was a global conflict that lasted from 1939 to 1945

World War II was a global conflict that lasted from 1939 to 1945, involving most of the world's nations. It was the deadliest conflict in human history, with an estimated 70-85 million fatalities. The war's origins can be traced back to the aftermath of World War I and the Treaty of Versailles in 1919. The treaty imposed harsh penalties on Germany, leading to economic hardship and political instability. This, combined with the rise of Adolf Hitler and the Nazi Party in Germany, set the stage for the conflict. Hitler's aggressive expansionist policies, aimed at overturning the post-World War I international order, were central to the war's outbreak. The immediate cause of World War II was Germany's invasion of Poland on September 1, 1939. Hitler sought to expand German territory and secure "living space" (Lebensraum) for the German people. This invasion prompted Britain and France to declare war on Germany, marking the beginning of the conflict. Over the next few years, the war expanded as Germany, Italy, and Japan (the Axis powers) pursued military campaigns across Europe, North Africa, and the Pacific. The tide of the war began to turn in favor of the Allies after significant battles such as the Battle of Stalingrad (1942-1943) and the Battle of Midway (1942). The Allied invasion of Normandy (D-Day) on June 6, 1944, marked a crucial turning point, leading to the liberation of Western Europe from Nazi control. World War II ended with the unconditional surrender of the Axis powers. Germany surrendered on May 7, 1945, after the fall of Berlin to Soviet forces. Japan continued fighting until the United States dropped atomic bombs on Hiroshima and Nagasaki in August 1945, leading to Japan's surrender on September 2, 1945. The war's end reshaped the global political landscape and led to the establishment of the United Nations in an effort to prevent future conflicts on such a devastating scale.