Three events in Europe which led to war in 1914.

There were many events leading up to world war, each doing its own significant part in causing the outbreak. Although they all had input in causing the war, it is obvious that certain events were historically more important than others. In the following, I shall identify those which I think are the most important and compare all of them to conclude which had the most influence leading to the war. Alliances and agreements between countries …

…assassination of Archduke Franz Ferdinand which causes the first domino to fall over, causing a chain reaction of war. Although the assassination was important, there's nothing to say that, had it never taken place, something else would have knocked over that very first domino and caused Austria-Hungary to declare war on Serbia. So in my opinion, it is the alliance system which turned out to be the most important factor leading up to World War 1.