Who Caused WW1

I don't think this can be blamed on any single country because several countries had done something to contribute to the cause.  Main countries in my opinion are Germany, Austria-Hungary, and Serbia.  Germany challenged France and won to prove that they can be a superpower in war.  Serbia and Austria-Hungary along with other countries wanted to expand in the Balkans Region and that lead to more tension between them along with other stuff.  Later, the Black Hand of Serbia assassinated Franz Ferdinand, the heir to the throne of Austria-Hungary.  During that time, assassinations were common but Austria-Hungary wanted a reason to declare war on Serbia.