The assassination in itself didn't really cause World War I. It
merely triggered it. Europe had been close to war for ages for a
variety of reasons that I won't go into right now.
Germany, Austria-Hungary and Italy were all allied. This meant
that if any one of them got attacked, the other two would pitch in
and help as well. This was called the Triple Alliance. Britain,
France and Russia did the same thing. This was called the Triple
At the time, Bosnia was part of the Austria-Hungarian empire.
However, some Bosnians didn't like this and wanted to join up with
their neighbours Serbia instead. Serbia also wanted to join up with
Bosnia. So, when the heir to the Austrian throne, Franz Ferdinand,
got assassinated in Sarajevo [the capital of Bosnia] in 1914, the
Austria-Hungarians blamed Serbia for it.
This would have just been a small war, fighting over Bosnia, but
if you remember Austria-Hungary was allied with both Germany and
Italy. So Germany and Italy got dragged into the war too.
Also, Russia had agreed to help Serbia, so Russia got dragged
in. Russia, in turn, was allied with France and Britain. By now,
most of the larger European countries were involved in the war, and
it just escalated from there.
I will do my best to answer this. The death of the Archduke lead to
global conflict because his death upset Austria-Hungry and they
wanted to attack Serbia but they knew that if they attacked Serbia
then russia would come to the aid of Serbia so they asked germeny
to back them if russia got involved and so Germany said ok so
Austria-hungry attacked and russia started to mobilize there troops
so Germany knew that somehow France was connected to russia so
Germany decided to wipe out France so that they would not have to
fight on both side of their borders. They decided to invade France
through belgum which got Great Britain involved. and the rest is
When Archduke Franz Ferdinand was assassinated Austria-Hungary
wanted to attack Serbia. They knew that if they attacked Serbia
that Russia would defend Serbia. SO, they asked Germany to back
them up if Russia were to attack them. Germany said Yes, so
Austria-Hungary attacked Serbia, and Russia declared war on
Austria-Hungary, and Germany declared war on Russia. Thus, WWII was