Well lets talk about it. Was Austria right in declaring war against Serbia? But was the start of the war think more then the murder of the Arch Duke and his wife!
Saw another thread touching on this, so I'll add something. What started out between Austria and Serbia engulfed the whole whole of Europe largely due to an elaborate set of political alliance that the European powers all lined up behind. I'm not sure they gave much thought to what the war was actually about.
I think it goes a little further then Serbia/Austria adventure. I would look towards France/Germany. Franco/Prussian War had not been so easy forgotten Germany still wanted more from France. More money, more land, France really needed to get back what she lost. Like u said it was about alliances...