World War I was the result of leaders' aggression towards other countries, which was supported by the rising nationalism of the European nations. Economic and imperial competition and fear of war prompted military alliances and an arms race, which further escalated the tension contributing to the outbreak of war.
             For twenty years, the nations of Europe had been making alliances. It was thought the blocks would promote peace. Each country would be protected by others in case of war, making it foolish for one government to wage war on another. The danger of these alliances was that an argument between the two countries could draw all the other nations into a fight. This is just what happened when a conflict between Austria-Hungary and Serbia led to World War I. Powers (Germany, Austria-Hungary, and Turkey). Prominent among the war's causes were the imperialist, territorial, and economic rivalries of the great powers. The German empire, in particular, was determined to establish itself as the preeminent power on the Continent. The Germans were also intent on challenging the naval superiority of Britain. However, it was rampant nationalism-especially evident in the Austro-Hungarian empire-that furnished the immediate cause of hostilities. On June 28, 1914, Archduke Francis Ferdinand, heir apparent to the Austro-Hungarian throne, was assassinated at Sarajevo by a Serbian nationalist. One month later, after its humiliating demands were refused, Austria-Hungary declared war on Serbia. Other declarations of war followed quickly, and soon every significant power in Europe was in the war.
             Some of the primary causes of World War I go as far back as the early 1800s. Peoples controlled by other countries began to develop feelings of nationalism. Countries grouped in rival military alliances to advance their aims. They fought for colonies and other lands. Finally, governments clouded international relations by carrying on secret diplomacy. On ...