At a local level in time people think things are fine, then things rapidly spiral out of control until they become unstoppable, and we wreak massive destruction on ourselves. For the people living in the midst of this it is hard to see happening and hard to understand. To historians later it all makes sense and we see clearly how one thing led to another. During the Centenary of the Battle of the Somme I was struck that it was a direct outcome of the assassination of an Austrian Arch Duke in Bosnia. I very much doubt anyone at the time thought the killing of a European royal would lead to the death of 17 million people.