Nationalism led to World War I by fostering intense pride and loyalty toward one's nation, which in turn created competition, tensions, and conflicts among European countries. Nationalism heightened feelings of superiority and distrust between nations, fueling rivalries and a desire for independence particularly in multi-ethnic empires such as Austro-Hungary. This created unrest and a volatile political climate, especially in the Balkans, where nationalist movements sought self-rule. The assassination of Archduke Franz Ferdinand of Austria by a Serbian nationalist in 1914 ignited these simmering tensions, triggering the outbreak of the war. Nationalism also intertwined with militarism and imperialism, leading nations to build up their military power and compete aggressively for colonies and global influence, creating a false sense of confidence about war outcomes. This combined atmosphere of fierce nationalism, military buildup, and imperial competition made large- scale conflict almost inevitable by 1914. Thus, nationalism was a deep-rooted cause that helped shape the conditions which led directly to World War I.