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. …

…help to Russia, her ally and Austria-Hungary asked for Germany to help. This would mean that Russia would be fighting Germany. The attack of Russia would then drag France and Great Britain into the War. So, the start of the War was just like a barrel of Gunpowder. Gradually the barrel was built and filled with explosive. One small event was "like lighting the fuse". It led to a big explosion called World War One.