The 50th anniversary of John F Kennedy's assassination has special significance for the group of Irish Army cadets who were asked to form an honour guard at the funeral on 25 November 1963.
With the eyes of the world on them, the young cadets performed their silent drill at Arlington National Cemetery in Virginia as Kennedy's grieving family gathered at his freshly dug grave.
Jacqueline Kennedy made the request because her husband had been so impressed by the drill performed at Arbour Hill during a visit to Ireland in June of that year.
Kennedy had described the drill as the highlight of his four-day trip and asked for a copy of the drill to be sent to him in the White House.
"That is the finest honour guard I have ever seen," Kennedy told Lieutenant Frank Colclough, the officer in charge.
The 36th cadet class who performed the drill had graduated by the time of Kennedy's request, so it fell upon the 37th class to perform the drill for the film and subsequently at the funeral.
As the world reeled from the shock of Kennedy's assassination in Dallas on Friday 22 November, the young cadets were recalled from leave to return to their base in the Curragh.
After hectic preparations on the Saturday night, and armed with their rifles, one holdall each, and some money from a local shopkeeper, the cadets travelled to Washington in the company of President Eamon de Valera.
Retired colonels Richard Heaslip and Martin Coughlan were among the 26 cadets selected from the 37th class to participate in the ceremony that was watched by millions of people around the world.
"When that tragedy dawned on everybody, this was a Friday evening, we were facing a Saturday morning inspection. Surviving Saturday morning's inspection was what it was about and then relaxation and local leave," said Ret Col Heaslip, who is the father of Irish rugby player Jamie.
Ret Col Coughlan said: "I think the phone call came through here at about 9.30 at night that the cadets were to be got back in here.
"I went to Newbridge with a few mates because we were always hungry then because you were so busy. It broke that we were probably going to Washington and we didn't believe it."
Other cadets, including Ret Col Heaslip, were at a local cinema.
"It all happened so quickly after that," he said. "It was the wrong time of the month too because we didn't have any money."
For many of the fresh-faced youngsters, it was their first time in an aircraft and the retired colonels recalled how surprised they were that President de Valera took the time to chat to each cadet.
"We were in Dublin Airport and 'Dev' decided he wanted to meet us personally," said Ret Col Coughlan.
"He came along and shook hands with each of us individually. We thought that was that, but somewhere across the Atlantic he came down along the plane and chatted to each one individually."
Once in Washington, the cadets had little time to prepare for their moment in the spotlight and rehearsed at Arlington on the morning of the funeral.
They returned in the afternoon and stood by the graveside for about two hours as the cortège made its way from St Matthew’s Cathedral in Washington.
Ret Col Heaslip recalled: "I don't think the solemnity or the aura and the mystique that was there dawned on us until, in a sense, we had the rehearsal by the graveside in the morning.
"We began to realise it then, but I think part of our brief was Frank Colclough telling us that 'remember the eyes on the world is on you and you have to perform'."
"How could Jacqueline Kennedy even remember to invite us?" wondered Ret Col Coughlan.
"It was remarkable. All the trouble she had – her husband had just been shot dead and she with him. It was years later that we realised the importance of the whole trip.
"The funeral was on Monday and on Tuesday, President de Valera wanted to lay a wreath on the grave and we did the honours there.
"The only night we had off was Tuesday night, when the American GIs took us out and showed us Washington. They looked after us very well."
This was the days before mass communication and some of the cadets' families were not aware they had taken part in the funeral until after they returned home.
Ret Col Heaslip said: "I don't know that my parents knew I was even in the States because there was no way of communicating because we didn't have a telephone.
"I think they had to wait for the publication of the Limerick Leader to see myself on the front page."
The men returned to Ireland on Wednesday 27 November 1963 and were back on duty the following morning.
It was the only time a foreign military has had a presence at a US President's funeral.
“It was a wonder for the time we were there. As old men we can reflect on it a little bit,” said Ret Col Heaslip.
Five members of the current cadet class will fly to Washington to perform the same drill 50 years on, while some of the original cadets will join them to mark the occasion.