Beacause of on 28th June 1914 Archduke Francis Ferdinand, heir to the Austria-Hungarian throne, was assassinated in Sarajevo, by a Serbian nationalist. Convinced that the Serbian government had...
Because of the murder of Franz Ferdinand :)
an act of terrorism
Austria declared war on Serbia because they were afraid of the Serbs joining Serbia so they were looking for an excuse to crush Serbia.
Where do u think.....in Austria...WOW....now is it hard to find information yourself?!? :)