The fundamental causes of World War 1 are usually considered to be a combination of long-term political, economic, and social tensions that had been building up in Europe for several decades. These include:
- Rivalry between the European great powers, particularly between Germany and Britain, France, and Russia.
- Imperialism and the competition for colonies and resources.
- Nationalism and the desire for territorial expansion.
- Militarism and the arms race between the European powers.
- The failure of diplomacy to resolve these tensions.
The immediate cause of World War I is generally considered to be the assassination of Archduke Franz Ferdinand of Austria, the heir to the Austro-Hungarian throne, by a Serbian nationalist in Sarajevo on June 28, 1914. This event sparked a chain of diplomatic crises and military mobilizations that led to the outbreak of war within weeks.