1. Militarism:
The major European powers engaged in a arms race, building up their military strength and preparing for war.
2. Imperialism:
The European powers competed for colonies and influence in Africa, Asia, and the Middle East, increasing tensions between them.
3. Nationalism:
Growing nationalist sentiment and the desire for self-determination among ethnic groups in Europe contributed to tensions between countries.
4. The Assassination of Archduke Franz Ferdinand:
The heir to the Austro-Hungarian throne was assassinated by a Serbian nationalist in Sarajevo, triggering a chain of events that led to war.