Today marks the 21st anniversary of 9/11. The loss of 3000 victims endures in our grief.

At this distance in time, for me, that was a day when the tone of life changed. Many of our current troubles date from then. Even if not all are linear descendants of events set in train that day, the optimism that followed the fall of the Berlin wall (1989) and, separately, the signing of the Belfast agreement (1998) seemed to fade quickly.