1. Nationalism: Nationalism, the belief that one's nation is superior to others, played a significant role in the build-up to World War I. Nationalism had been on the rise in Europe throughout the 19th century and had led to increased competition and conflict between different countries.
2. Imperialism: Imperialism, the acquisition and control of colonies by powerful countries, was another key factor in the outbreak of World War I. European powers were competing for control over resources and territories in Africa, Asia, and the Middle East, and this competition increased tensions between them.
3. Militarism: The build-up of military forces by European countries was a major factor in the outbreak of war. Countries were competing to build up the largest and most powerful militaries, and this led to a climate of fear and suspicion among them.
4. The Assassination of Archduke Franz Ferdinand: The assassination of Archduke Franz Ferdinand, the heir to the Austrian throne, on June 28, 1914, was the immediate trigger for World War I. The assassination led to a series of diplomatic crises and misunderstandings between Austria-Hungary, Russia, and Serbia, and ultimately led to the outbreak of war.
It is important to note that these factors were not the only causes of World War I, and there were many other complex and interconnected factors that played a role in the outbreak of war.