What caused World War I?

World War I was a result of the economic and political tensions and ambitions of the Great Powers of Europe at the beginning of 20th century. In the period between 1871 and 1914 the war between these countries was avoided only by the help of diplomacy and concessions. However, in 1914 diplomacy could no longer solve the conflicts between the nations. <Tab/>The rivalry began in 1871 when Prussia (Germany) defeated France in the Franco-Prussian …

…of July Russia supported Serbia in the war against Austro-Hungary. On the first of August Germany helped its alliance Austro-Hungary by declaring war on Russia. On the second of August France joined on the side of Russia and Serbia. This enabled Germany to attack France through Belgium. Finally, on the fourth of August Britain joined Russia, Serbia and France against Austro-Hungary, Germany and Italy. <Tab/>The World War I has begun.