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.
<h3 /><h3>What causes the
World war 1?</h3>
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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