No one will ever forget where they were, when they heard that planes had been flown into New York's World Trade Centre, the Pentagon, and a field in Pennsylvania.
Irishman Paul McCormack is a former NYPD Officer involved in the recovery mission at Ground Zero.
He says it's a punch in the gut to hear calls for help, when no help is coming.
"As a member of the NYPD. We never prepared for something like that, it a incident that you, just nobody could have prepared for that. And we weren't ready for it. I was in my office at the 41st precinct, I was the commanding officer of the 41st precinct, on 9/11, when the towers went up and it was a stunning breath-taking event, and all hell broke loose."