* Nationalism: The early 20th century was a period of intense nationalism, with each European country seeking to assert its dominance and power. This led to increased competition and rivalry among the major European powers.
* Imperialism: The major European powers were also competing for control of colonies and resources around the world. This led to increased tension and conflict between the powers.
* Militarism: The major European powers had built up large militaries in the years leading up to the war. This created a sense of insecurity and fear among the powers.
* The Balkans: The Balkans, a region of southeastern Europe, was a major source of tension between the European powers. The region was home to several ethnic groups, and each power had its own interests and ambitions in the region.
The assassination of Archduke Franz Ferdinand of Austria in 1914 was the spark that ignited World War I. The assassination led to a chain of events that eventually resulted in the outbreak of war between Austria-Hungary and Serbia. Russia, which had a defensive alliance with Serbia, entered the war on Serbia's side. Germany, which had an alliance with Austria-Hungary, entered the war on Austria-Hungary's side. France, which had an alliance with Russia, entered the war on Russia's side. Britain, which had a treaty with Belgium, entered the war after Germany invaded Belgium.
The war lasted for four years and resulted in the deaths of millions of people. It ended with the signing of the Armistice of 11 November 1918.