That was the spark that lighted the fuse to set off WW1, there were several items that contributed, such as the arms race between Britain and Germany, The Balkan question of independance from the Austro-Hungarian Empire with the rebel Serbians being aided/supported by Russia, Germanys recent defeat of France late the previous century, Empire ambitions of Germany and Britain. The feeling of Nationalism amongst each participants civilian population. New weapons such as the Dreadnought Battleship, aircraft, machine guns, each side stockpiling these weapons, what is the justification of spending money on these weapons if your not going to use them? Also money as always.