Why did World War I Break Out in 1914?

In this essay I am going to be explaining the causes of WWI. There are four main causes of WWI. They are Nationalism, Imperialism, Militarism an Alliances. The assignation of Archduke Ferdinand was only the 'spark' which set off the 'barrel of gunpowder'. The four causes had created so much tension in Europe that it only needed one event to trigger war. I will break down the four causes in to long-term, medium-term and short-term. The first long term cause is Nationalism.
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