World War 2 was caused by a series of events that led to the polarization of both the Axis powers and the Allied forces. These events increased tension and aggression which erupted into full blown war by 1939. There are four major events that led to World War 2.
The Versailles treaty was among the major turning points in the build up to the war. The leaders of the Allied forces such as Lloyd George, Clemenceau and Orlando of England, France and Italy respectively, together with Woodrow Wilson wanted to sign a treaty that would foster peace in the world. However, the British and French leaders had other motives in the treaty hence; they altered its terms. Germans did not agree to this treaty, and this raised tension as Hitler promised never to adhere to the terms.
The rise of Hitler to power was another cause of the war. He came to power in 1933 and began building the military base of the nation. He also focused on increasing the armory of the country such as building warships and developing an air force. Hitler had clear intentions from the start of his reign to begin a war against the Allied forces. Finally, Hitler ordered the attacks on other countries such as Austria and Hungary.
The appeasement policy by the Allied forces was also a cause of the war. While the Germans were invading and occupying other countries, the Allied forces stayed cautious. Even when it was clear that the Germans were arming themselves for possible war, Britain and France did not take any action because they were not prepared for war. However, this was a heavy price because it led to another world war.
The disintegration of the League of Nations was also a cause to the war. The league had been established after the Great War to promote international peace. However, not all nations were its members. The league failed because it had limited power over its members. It had no army, it did not act fast, and not all countries were part of the league. The formation of the Allied forces and the Axis forces was also a recipe for war.
Therefore, these events increased tension, polarized the axis and allied powers then exploded into war in 1939. The events that led to the war had begun after the Great War and through the great depression.
Calvocoressi, P., Wint, G., & Pritchard, R. J. (1989). Total war: the causes and courses of the Second World War, Volume 1 (2, revised, illustrated ed.). London: Pantheon Books.
Crozier, A. (1997). The Causes of the Second World War (illustrated ed.). New York: Wiley.