Which if any countries were responsible for causing World War 1?

Short answer is all the countries of Europe were largely responsible. They all spent 30 years building treaties that pitted the sides against each other, conquering and coveting each others foreign colonies and indulging in arms races. The war was easily predicted by many for up to a decade in advance, but no one probably could have imagined the actual carnage. Germany is largely seen as being responisble for being to over eager to go to war for Austria following the assisination of Archduke Franz Ferdinand by Serbian nationalists.