World War I.
Austria-Hungary declared war on serbia and Germany joined because it was allied with austria.
It was the spark that began World War 1.
Austria-Hungary, Serbia and in a way Germany because they were backing Austria-Hungary
The single event that started a chain of other events that led to World War 1 was the assassination of Archduke Ferdinand. This event took place in June of 1914. Archduke Ferdinand was the heir to the Austro-Hungarian throne.
Austria declared war on Serbia
The assassination of the Archduke was important because it marked the start of WW1. Austria-Hungary then declared war on Serbia[the assassins] and because of all the treaties the countries have, it turned into a world war.
Because the archduke wanted peace, but everyone in Austria disagreed
There are severa reasons that come to mind. One of the major reason why WW1 started was because o the assassination of Archduke Ferdinand of Austria.
The assassination of the Archduke was a deadly event in the history of European peace. This is because that killing is what led to the First World War.
The cause of World War 1 was because of the assassination of Archduke Franz Ferdinand. Ferdinand was the next in line for the throne of Austria. Austria then put the blame on Serbia, starting World War 1.
They went to war with Serbia, which was backed by Russia, which was backed by France ... and Britain.
The assassination of Archduke Franz Ferdinand of Austria in 1914.the war was being planned for a long time before it actually broke out, and this was because of the assasination off Franz Ferdanand.