How Has 9/11 Changed Our "Physical World" Over The Past Ten Years

I interviewed my dad and he said, "The 9/11 has changed the world because it gives a new meaning to the war and the way we should look at the national and human security. The war is no longer between the two or more sovereign nations but it can goes beyond the territorial border. The parties or the players in this new war are not necessarily from the military or state armed forces (with uniform) but it can be anybody including the civil society."