The World War of the 20th Century was amongst the greatest and most lethal of all modern warfare. It was a horrific time whereas almost every civilized nation in the world was effected one way or the other. Despite the twenty-three year armistice, World War Two was merely Part Two of the First World War with higher stakes due to the fact that the same conflicts were never resolved (by the League of Nations), just drawn deeper into. There were also the same recurring factors such as nationalism, imperialism, and militarism.
Nationalism is defined as an intense loyalty to one's nation. It serves as an important factor to uniting people in one's own nation. Unfortunately, it does not apply to international affairs because they can also invoke powerful rivalries and competition amongst them. And that was exactly what had happened when the success of industrialization in various starting in the middle of the 19th century started to challenge British supremacy in industry, finance, and shipping. The most radical of those was Germany. And aside from competition with Britain, there is also bitterness on the side of the French when they ceded Alsace-Lorraine to Germany in the Franco-Prussian War of 1870.
Militarism also ties in very closely with Nationalism. Wilhelm 2, the Kaiser of Germany was said to have been the one to lead his country into the First World War. Military might had always been his uttermost important concern for Germany. He was the one who led the campaign of extensive shipbuilding to go against the British Navy. The Kaiser urged nationalism by the way that he thought of Germany and himself the greatest power in Europe:
"There is no power in Europe but me-me and my twenty-five army corps."
All of the Great Powers of Europe (except Britain) had succeeded in building large armies by 1914. They all felt the need to measure their worth and greatness by the power of their armies. They had already begun preparing for war by