World War I & It's Causes

World War I was the cause of a number of interwoven factors that further escalated the tension contributing to the outbreak of war. The assassination of one of Austria's arch dukes, Franz Ferdinand, by Serbia set off a chain of events. Austria attacked Serbia, Russia attacked Austria, Germany attacked Russia, and so on and so forth. Okay now to get to a more detailed cause, many rivalries sprouted all over Europe due to nationalism. At the settlement of the Congress of Vienna in 1815, the principle of nationalism was ignored in favor of preserving the peace. Nationalism posed a problem for Austria and the Balkans, which were areas compromised of many conflicting national groups.
Another cause which contributed to the start of the war was imperialism. The Industrial Revolution caused a need for foreign markets because of the increase in manufacturing products.
Great Britain, Germany and France competed for economic expansion in Africa. Several events foreshadowed the war between European nations during this competition.
Finally I'd say the biggest cause would be Ferdinands assassination, which wasn't explained fully at the top. The arch duke and his wife were shot dead by a young Serbian nationalist of the Black Hand at Sarajevo. The Black Hand assassinated him because he wanted to convert the Austro-Hungarian Monarchy into a Triple Monarchy by the inclusion of Serbia. Franz was also heir to the Austrian throne and so his ideas might have a chance for realization very soon. The reigning monarch , Francis Joseph, was 84 years old and seemed to be nearing his peak so his death was expected soon. The black hand decided to act fast and assassinate the heir that would bring a change they didn't want to their nation.