The '''causes of World War I''' vary from the immediate (the assassination of the heir to the Austrian throne by Serbian nationalists, to the complex (such as ethnic nationalism across Europe, the arms race, and the competing alliance systems) to the remote (the [[Franco-Prussian War]] of 1870-1871). | The '''causes of World War I''' vary from the immediate (the assassination of the heir to the Austrian throne by Serbian nationalists, to the complex (such as ethnic nationalism across Europe, the arms race, and the competing alliance systems) to the remote (the [[Franco-Prussian War]] of 1870-1871). |