The invention and use of the tools of war: Machine Guns, Constant Artillery bombardment, Barbed Wire, Tanks, Aircraft, Submarines, Flamethrowers, Grenades, High Explosive... All came down to the suffering of individual soldiers, it becomes painfully obvious why World War One happened the way it did once you see this video... Some sobering statistics are below... The total number of military and civilian casualties in World War I was over 35 million.