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.
The rivalry began in 1871 when Prussia (Germany) defeated France in the Franco-Prussian war. Since then France and Germany were constant enemies. The division of Europe in two "camps" was, too, a major issue in the cause of the WWI. In 1882 Austro-Hungary, Germany and Italy formed the Triple Alliance with which they stated that in time of war they will defend each other.
When in 1888 William II became the new Kaiser of Germany he decided that he will make Germany a sea power comparable in size with that of Britain.
And by 1897 he had increased his sea navy and thus made German the second biggest sea powering Europe. Britain feared that Germany will become too strong on sea, so it, too, increased its navy by the start of the Dreadnought.
In the year 1905 (and again in 1911) Germany questioned France's authority in Morocco (by declaring Morocco a free country). Britain interfered and made Morocco a French province thus avoiding the war between Germany and France.
By the year 1907 France, Russia and Britain were already concerned by the triple alliance between Austria-Hungary, Germany and Italy because together they formed a dangerous enemy in times of war. So France, Russia and Britain decided to form the Triple Entente not so to help each other in time of war but to "encircle" the Triple Alliance. Thus the complete division of Europe was finished.
The event that...