The First World War broke out because of a system of two major European Alliances. These started a war due to Germany's ruthlessness, and caused a European war. Then the nations' colonies joined in, and eventually all of the world's major powers had joined in, causing the First World War.
Before the main events of the war, two main alliances had been formed. Germany had defeated France in the Franco-Prussian war in 1871. 3 000 French soldiers were killed, 14 000 wounded, and about 100 000 captured. Most importantly, the Emperor Napoleon III was captured. Ever since 1871, Germans had been worried that France would attack them, so they sought alliances with the other major European nations, so France would be isolated. By 1882, Germany was allied with Austra-Hungary and Italy, in an alliance called the Triple Alliance. Then, in 1887, they signed the Reinsurance Treaty with Russia. Thus Germany was allied with three major European nations and France was left isolated.
Russia
Russia
Count Leopold von Berchtold, Imperial Foreign Mini...In 1890, the German kaiser set out to make Germany a major world power. He aimed to increase the number of Germany's overseas colonies. To do this, Germany increased the size of its navy. Britain's Royal Navy was the world's largest navy at the time, so Britain felt threatened and challenged by Germany's naval build-up.
Also in 1890, the alliance between Germany and Russia was dropped. To stop its forced isolation, France allied with Russia in 1894. Germany was hence surrounded by France and Russia, and they felt threatened. The continued increasing their navy, making Britain feel threatened, also. Britain decided to ally with France and Russia, just in case Germany attacked. Thus, the Triple Entente was formed. The Triple Entente, made up of Britain, France and Russia, opposed the Triple Alliance, which was Germany, Italy, and Austria-Hungary.