Did the assassination of Archduke Franz Ferdinand actually cause WW1?

In history, we learned that the assassination of archduke Franz Ferdinand caused World War 1, but I was thinking about it and I found it really hard to believe that it actually caused an entire war. Sure, Austria didn't like Serbia, but was one assassination enough to cause Austria to invade? <br><br>Was it just an act of aggression from Austria and Germany or was it actually because of the assassination?