Their numbers are diminishing.
Those prepared to give their lives in the war against Hitler.
Harold 'Johnnie' Johnson is one of them. He flew dozens of operations on Lancasters and recognises he was fortunate to survive when so many of his colleagues and friends died.
Now aged 95 and increasingly frail, Johnnie's achieved one of his final ambitions - visiting the memorial that recognises the sacrifice of the thousands from Bomber Command who were killed.
Friends in Norwich organised the trip to London. While they travelled by coach, Johnnie - recovering from a recent bout of pneumonia - went by private ambulance.
His visit was even more emotional than he expected it to be .
Tears rolled down his cheeks as he surveyed the memorial unvelled by the Queen less than a year ago.
"It's terrfific," he said. "This is for all those who didn't come back."
"Its been his dream and ambition to see this," revealed Maurice Morson, from the Norwich City Police Association which arranged the trip. Johnnie was a police officer in his native London before the war, and in Norwich after it.
– Maurice Morson
"t took the politicians 70 years to recognise what Bomber Command did and we're just glad that Johnnie's had the chance to see it
For Johnnie, there's still a sense of annoyance that it took so long to create a proper tribute to a group that suffered the biggest loss of life in the 2nd World War. More than 55,000 were killed.
– Johnnie Johnson
We seemed to get the backlash because of the loss of life from bombings on Dresden that the Russians wanted us to carry out.
"It didn't seem fair. We lost a lot of very good men. Actually, most of them were just boys. The pilot on my Lancaster crew was just 18 when he started. Most of those I flew with were about 20.
Johnnie won the Distinguished Flying Cross for his wartime heroics. He's not to be confused with George 'Johnny' Johnson, the last surviving British crew member on the Dambusters raids or the Spitfire fighter ace Johnnie Jonson.
The Bomber Command Memorial is a tribute to all those who played a part in raids over Germany. Johnnie was a bomb aimer on Lancasters and admits to being frightened.
"The first tine we went to Berlin and saw what we had to go through - the seachlight barrage - I didn't think we'd come back. I thought that was the end."
He even survived a fearful ticking off from his commanding officer for not seeking permission to marry his fiance Enid. She was a non commissioned officer in the RAF and as such wasn't considered right for Johnnie.
But they did marry. Sadly, Enid died a few years ago but other members of his family were at the memorial to witness a very proud day in Johnnie Johnson's life.