The World war 1 started when Au.stria-hung.ary declared war on S.erbia one month after Franz Ferdinand of Austria and his wife were killed by a Serb.ian nationalist.
What causes the World war 1?
The main cause of the was the assassination of Franz Ferdinand of Aust.ria whose murder plunged the Europe continent to war that lasted until 1918.
In conclusion, the World war 1 started one month after Franz Ferdinand of A.ustria and his wife were ki,lled by a Se.rbian nationalist.
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