World War II was a global conflict that took place between 1939 and 1945. It was the largest and deadliest conflict in human history, resulting in the deaths of an estimated 70-85 million people, many of whom were innocent civilians. The war’s causes are manifold and difficult to pin down, but historians agree that World War I, which ended in 1918, had left the world with many unresolved problems. Germany had been seen as the primary aggressor in World War I, and the 1919 Treaty of Versailles demanded that the country pay economically devastating reparations to the countries it had harmed. The treaty also restricted Germany’s military in order to prevent it from once again becoming capable of threatening Europe. By the early 1930s, these measures had given rise to substantial resentment among segments of the German public—resentments that were only exacerbated by the global economic depression that began around 1930. Adolf Hitler took power by leveraging these resentments and by scapegoating Germany’s Jewish population, exploiting the antisemitism that had long been present in Germany, as in much of Europe. Hitler was elected Chancellor of Germany in 1933, whereupon he rapidly consolidated power, transforming Germany from a parliamentary democracy to a totalitarian state within a few years. In 1939, he began his plan “to take over the world” (4) by invading Poland. This invasion is largely seen as the start of World War II. Shortly after, Britain and France declared war against Germany, but Germany continued to conquer much of Europe, including France in June 1940. In September 1940, Germany began bombing Britain and signed the Axis alliance with Italy and Japan.

By 1941, Germany had begun the Holocaust, a systematic murder of European Jews that would result in over six million deaths. Throughout 1941, the war expanded abroad as well, as Germany marched on the Soviet Union and Japan attacked Pearl Harbor, causing the United States to enter the war. Throughout 1942, ’43, and ’44, the Allied nations, including the United States, the Soviet Union, China, and Britain, began to regain ground taken by the Axis powers. The Western Allies successfully invaded Germany and forced the nation to surrender on May 8, 1945. In August 1945, the United States dropped two atomic bombs on Japan, killing hundreds of thousands of civilians and forcing the country’s unconditional surrender. Japan’s official surrender document was signed on September 2, 1945, signaling the official end of World War II.

World War II reshaped the world politically, socially, and economically, establishing structures, like the United Nations, that continue to constitute the bedrock of international relations around the world.