Another reason why World War One broke out was Nationalism. Many people in Europe lived in countries that were part of empires. They didn't all like being ruled by people with different languages and religions and this led to conflicts that involved other nations. An example of this is Serbia. In 1908, Austria-Hungary officially took over Bosnia and Herzegovina, which then all became part of the Austrian-Hungarian Empire. Serbia protested strongly. Serbia wanted independence, they protested because millions of Serbians lived in Bosnia and Herzegovina. Even though Austria-Hungary offered Serbia an equal partnership to join their empire (Trialism) they rejected the offer. They didn't want to be part of Austrian-Hungarian empire, they wanted to be part of an independent Serbia. Russia backed Serbia's protest, and Germany decided to support Austria-Hungary. War did not break out, but this whole scenario again caused great tension between the two.
Britain and Germany were competing in an arms race to have the most powerful navy in the world. Around 1889, Germany were building up their Navy, it quickly became a clear danger to the British, who were worried that they would lose control of the seas. After the Triple Entente was formed, Germany claimed that they were surrounded by enemies, this gave them an excuse to keep building their Navy. Armies were also greatly expanded, France and Germany’s standing armies doubled between 1871 and 1914. Once their armies were big enough, the leaders would want to test them out and this could and would lead to war.
Another factor, which contributed to the outbreak of World War I, was Imperialism. All the leading European countries wanted a larger and more powerful empire, and they would do anything to get one. In 1906, France had succeeded in taking over Morocco, despite Germanys attempt to stop them. Another example of Imperialism was the Balkans in southeast Europe. Austria-Hungary was small and they wanted to expand their empire. They did so by taking over Bosnia and Herzegovina in 1908. This greatly annoyed Serbia (who were supported by Russia) as many Serbians lived in Bosnia. War was inevitable now.
In the capital of Bosnia, Sarajevo, on the 28th of June 1914, the heir to the Austrian throne, Archduke Franz Ferdinand was assassinated. He was killed by a young Serb nationalist, Gavrilo Princip. This was the potential spark that caused war to be declared. Even without this spark, it was just a matter of time until war broke out.
Overall, there are many reasons why the war broke out, this essay covered the more important reasons. I think that the most important reason that led to the outbreak of the war were the different alliances, and the tension and entanglement between them. Due to all the tension build up between all the countries, war was bound to happen sooner or later, and did so, being sparked by the assassination of Archduke Franz Ferdinand.
