World War II
The war began in September 1939, when Germany invaded Poland, and quickly spread as other countries joined the conflict.
World War II (1939-1945) was a global conflict that involved the majority of the world's nations, including all of the great powers, organized into two opposing military alliances: the Allies (led by the United States, the United Kingdom, and the Soviet Union) and the Axis powers (led by Nazi Germany, Fascist Italy, and Imperial Japan). The war began in September 1939, when Germany invaded Poland, and quickly spread as other countries joined the conflict.The main causes of World War II were the aggressive actions of the Axis powers, particularly Nazi Germany, and the failure of the international community to effectively address these actions.
The Treaty of Versailles, which ended World War I and imposed harsh penalties on Germany, is also seen as a contributing factor to the outbreak of World War II.The war was fought on multiple fronts, including the Western Front (which saw some of the bloodiest and most destructive fighting of the war), the Eastern Front, and the Pacific Theater. It was also the first war in which nuclear weapons were used, when the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August 1945.
World War II resulted in millions of deaths and injuries and had a profound impact on the political and social landscape of the world. It also led to the collapse of several empires, including the Nazi regime in Germany and the imperial government in Japan, and contributed to the rise of the Cold War between the United States and the Soviet Union.The war officially ended on September 2, 1945, when Japan signed the Instrument of Surrender, and the United Nations was established to promote international cooperation and prevent future conflicts. World War II is remembered as one of the deadliest and most destructive wars in history.