There are many different factors that contributed to the outbreak of WWI. The most important of these are imperialism, the arms race, the alliance system, nationalism and the assassination of the Austrian Arch Duke. Although Germany has a share in the responsibility of these factors, she was definitely not the lone cause. Many powerful European nations played a roughly equal part in their contribution, which consequently started the First World War.
At the beginning of the 20th Century there was great imperialistic rivalry in Europe. This rivalry can be referred to as the "root" of all the major causes of World War I. Imperialism led to strained relationships between the powers (Germany often clashed with Britain and France over the rule of African countries, and France rivalled with Italy over Tunis) which led indirectly to the formation of the alliance systems. It also led to an intensification of the arms race. In 1896 Dr. Jameson made a raid into the Dutch Republic of Transvaal in South Africa. Germany found that, without a navy, she could not send much military help to the Dutch. Shortly after the event, Admiral von Tirpitz, the German Minister of Marine, proclaimed the need of a strong navy. From 1898 onwards, Germany built more battleships. This produced competition between Britain, which wanted to maintain its position as the strongest naval force in Europe. The responsibility with the problems caused by imperialism lay with all the major powers equally. The nations all acted too selfishly in wanting to expand imperial power even further, especially Britain who could not stand German competition both militarily and imperially.
In the beginning of the 20th Century, nationalistic spirit had been growing amongst the people that lived in the European Empires. This spirit came to an eruption when on July 1914 the Austrian arch duke was assassinated in Sarajevo, Bosnia-Herzegovina.