Austria felt that Serbia was overreaching its territorial boundaries and that the only way to forestall it was a preventive war. The death of Ferdinand provided a convenient excuse to go to war with Serbia. In support of Serbia, Russia mobilized its forces against Austria-Hungary, who had declared war on Serbia. Germany declared war on Russia. The United Kingdom and France, allies of Russia, also entered the conflict.
A web of alliances existed between many European countries. Austria allied with Germany, and Serbia allied with Russia. The alliances obligated each country to go to war on behalf of its allies. This dragged more and more countries into the war. The war pitted the Central Powers, consisting of Germany, Austria-Hungary, the Ottoman Empire and Bulgaria, against the Allied Powers, consisting of the United Kingdom, France, Russia and Italy. The United States ultimately entered the war on the Allied side.
Many fascist leaders such as Adolf Hitler seized power in Europe by taking advantage of the hurt that citizens felt after WWI, especially in Germany.
Hitler was a veteran of WWI, and was disgusted at how weak his country had become after the implementation of the Treaty of Versailles. Germany was in ruins, and the people were suffering, so Hitler came in and offered the people a way to get back to their place of power.
Through popular political tactics, and intimidation by the street soldiers of the fascist parties who went out and burned buildings and terrorized citizens, fascists were voted into power, and then took over the government, establishing their regimes.
