I believe that the first and main cause of World War One was alliances. Alliances were a lot of things during those days. Security, safety, friendship, etc. But with alliances came a risk, opposing countries such as Germany, Austria/Hungary saw these alliances as threats. When Britain, France and Russia formed the 'triple entente', the Germans felt surrounded by the alliance. What did Germany do then? Form an alliance of their own with Austria/Hungary and the Ottoman Empire. This was hair raising news for the Triple Entente, thus the arms race began. I believe this is a valid reason as to how World War One was triggered because of how each country/alliance wanted to become one step ahead of each other.
I believe that widespread militarism was the second cause of World War One because of the arms race between Britain and Germany which sprung not only a feeling of jealousy between each country, but it also left a feeling of hatred between the two powers. In 1906, Britain released the HMS Dreadnought, not long after, Germany released their own battleship, nearly a replica to Britain's. This increased tension and nerves in this rivalry, with the arms race between each country came the prime time to start a war because of how much these two colonies began to despise each other. I believe this is a good cause of World War One because the competition between the two nations started the building up of their arm's, which led to an increase of distrust. Militarism and