World War 2: Causes, Key Events, and Global Impact (1914–1918)

World War II was a global conflict fought from 1939 to 1945, involving most major world powers. It was caused by political instability after World War I, the rise of fascist regimes, economic hardship during the Great Depression, and the failure of international institutions to stop aggression. Expansionist policies by Nazi Germany, Imperial Japan, and Fascist Italy led directly to war.

The conflict began in September 1939 with Germany’s invasion of Poland. Key events included the invasion of Western Europe, major battles on the Eastern Front, Japan’s expansion across Asia and the Pacific, and the United States entering the war in 1941 after the attack on Pearl Harbor.

World War II resulted in 70–85 million deaths, including the Holocaust, in which about six million Jews were murdered. The war ended in 1945, reshaping the global order through the creation of the United Nations and the start of the Cold War.