British Holocaust survivors and their liberators gathered in London's Hyde Park on Friday to mark the 60th anniversary of the liberation of the Bergen-Belsen concentration camp. Survivors say they will not allow what happened to be forgotten.
Liberators and survivors were among the speakers
Rudi Oppenheimer, 73, lost both his parents at Belsen just before its liberation.
He was 12.
"The main reason today meant so much for me is because they died there," he says.
Earlier he told a modest gathering at the park's Holocaust Memorial the world had "stood by" and let him be incarcerated "only because I am a Jew".
"I am the little boy who stood at the barbed wire fence at Belsen and saw," said Mr Oppenheimer, who lives in west London.
"I am the witness and you people here in the audience have heard me," he added.
He was due to fly back to Belsen later - the eighth time he has returned.
"At the moment, I feel fine, but it's when you get there that it hits you," he told the BBC News website.
"When you realise what happened, the memories come rushing back," he said.
Most of his previous trips back have been with British children and students, as part of his work with the Holocaust Educational Trust.
Immediately before the remembrance ceremony he joined fellow speaker Chief Rabbi Dr Jonathan Sacks and former soldier Frederick Smith, who helped liberate the camp, in a trust-organised visit to Camden School for Girls.
"I find it so rewarding and important to share my experiences with young people who might not otherwise know what went on," he says.
Mr Helfgott and Mr Oppenheimer give regular talks to children
This is a sentiment shared by his friend Ben Helfgott, 75, from Harrow, north London, a trustee of the educational trust who was also at the ceremony.
He said: "Today's service brought it all back but then I am reminded of what happened all the time.
"I've made it one of my life's missions to ensure that people don't forget - we must learn the lesson so that others don't have to suffer.
"No-one can suffer the way we suffered and it's impossible for anyone to understand but we must get the message across."
As well as Mr Oppenheimer and Dr Sacks, who recited a memorial prayer "for martyrs of the Holocaust", the ceremony was also addressed by the head of the British Army, General Sir Mike Jackson.
British liberators found piles of dead bodies
Other speakers included Holocaust Educational Trust chairman Lord Janner and president of the Board of Deputies of British Jews Henry Grunwald.
Karen Pollock, spokeswoman for the Holocaust Educational Trust, which also organised the ceremony, said the service had been "right and fitting".
She said: "Belsen was the only camp liberated by the British.
"It was the horrific images of Belsen broadcast into the nation's living rooms that first brought the holocaust home."
Those horrific images were seen at first hand by 82-year-old Victor Long, of Essex, a former SAS member who was one of the first British soldiers to enter the camp 60 years ago on Friday.
He said: "After we entered the camp, one of the first things we came across was a huge open grave that was almost full of dead bodies.
"There were lots of dead bodies everywhere and the people that were alive were in a bad way. We weren't allowed to leave the camp until we'd been fumigated because there was so much disease around."
Mr Long said it was "impossible to forget" some of the things he saw at Belsen.
"Today has brought things back - these memories stay with you, you can never forget."
He said he agreed with the head of the British army Jackson who, in his earlier address, made clear who he thought of as the real heroes of Belsen.
"I don't believe that those soldiers were the only heroes," Sir Mike said.
"The real heroes were those who suffered so in the camps - what they had to go through is almost beyond comprehension."