History--WW1

Obviously, 1870 is the turning point of the European history.
The unification of Germany and Italy remapped the balance of power in European Continent. The influence and status of the Hapsburg family reduced and was kicked out from the Italian and German states. Before 1848, there were only 2 powers in European continent, which were France and Austria. But in 1870, there were 4, which were France, Austria, Germany and Italy.
"Balance of Power" disappeared since 1870. Germany had defected Austria and France respectively in 1866 and 1870, together with her economic power, Germany, a new state, became the most powerful state in Europe. At that time, no one had enough power to stop German expansion. However, there is no more space for German expansion in Europe, which led to her overseas expansion, and finally become the rivalry bewteen Germany and Britian and France in early 20th century.
The Hapsburg family lost all of her influence in German and Italian states, she could only keep the eastern part of her empire. So in order to compensate her lost in Western Europe, Austria would like to spread her influence and further controlled the Balkans, and finally led the conflict with Serbian and worsen the political status among the Balkan states.
France was defeated in 1870. French army was lost, French Emperor was captured, the Versailles Palace was used for the crowned place of German Emperor. All of the above were serious humiliation to the French people. They were full of sense of revenge. French government understood that she was politically isolated in Europe, so she start to serach for her allies to prepare the second war with Germany.
Also, when we recalled how the unification movements were completed. Both German and Italian unification were completed by wars !! It did have negotation before, but it was proved to be useless in the 1848 revolution. So in European power's mind, war was the only method to solve furtue dispute !!!