The images are eerily reminiscent: the huge mounds of flower bouquets, the thousands in tears gathered in silent vigil outside the restaurants and concert hall where so many were killed.

In New York we had gathered outside fire stations to remember the noble dead who had given their lives trying to save others. It was impossible not to cry thinking of all the young brave lives lost.

There were also posters of missing ones, the image that most disturbed me after 9/11 when lampposts everywhere in New York were filled with posters of missing loved ones as desperate relatives sought them out.

The acts of heroism are there in Paris too, many of which were anonymous: the man with the red sweater who pulled numerous people out of the packed exit door of the theater as the mad men continued to shoot, the man who ran with a badly injured woman carried on his back, the strangers who opened their homes to the injured and those fleeing. Then there was the French soccer team who refused to leave the stadium after learning the German players had to stay the night there because airports were closed.

It was similar on 9/11 after the Towers fell and people fled uptown: restaurants opened their doors, apartments were made available and human life returned to its best aspects after displaying its worst excesses of hate and murderous activity just hours before.

In the end we are all Paris like the world was New York back on 9/11 and the scenes will bring fear and uncertainty to every big western city.

It is a time when we look for grand gestures of hope. I especially loved the story of the pianist, Davide Martello, who rode his bicycle into Paris hauling his grand piano behind him. He and his piano had traveled all the way from Germany.

The Irish Times noted that the “man who played John Lennon’s 'Imagine' on a grand piano outside the Bataclan theater in tribute to the victims of the Paris attacks has been identified as German pianist Davide Martello.” Apparently he brings his grand piano along to play at many the world’s trouble spots.

He set up the grand piano after he reached Paris outside one of the killing fields and beautifully played John Lennon's anthem "Imagine." In the video you can see the people present wiping away tears.

In a message posted online following his return home, he said: “I just got back home in Germany safe and tired from a 24h drive. Everything started in an Irish pub in Konstanz while I was watching the soccer match between France and Germany. After I saw that insane violence I just followed my heart and went to Paris with my piano. That was one of my most touching moments in my life and I need to rest and reflect about what happened in this short time.”

Well done to him and to all who seek to bring comfort to the families of the deceased and injured, who number in the hundreds.

The French government has already stepped up their military actions, attacking the The Islamic State of Iraq and Syria (ISIS) bases on Sunday and sending a strong message that the acts will not go unpunished.

We are at an inflection point in our world similar to 9/11. As free people in democratic countries we cannot live in permanent fear of such awful terrorism. The entire Arab world has to wake up to the reality that it is being done in their name whether they like it or not. The hate mongering will only end when the people themselves undertake to protest the actions of the dreadful groups in their midst.

The Roman Empire fell when the Visigoths and Huns joined forces to bring it down and Barbarians and Vandals joined in. In many ways Western civilization faces the same epic battle now against the barbarians at the gate who think nothing of killing innocent people by the thousands.

It is past time for the world powers to say enough and crush them underfoot. Let there be no more New York or Paris killings or anywhere else either.

Read more: An Irishman in Paris “The Barbarians are at the Gate”