The UK's Holocaust Memorial Day commemorations have begun with a concert in Cardiff attended by around 100 genocide survivors and rescuers.
The theme of the UK's sixth Holocaust Memorial Day is paying tribute to the rescuers of the Holocaust.
Here the BBC Wales news website talks to Eva Clarke who believes her life was saved by the kindness of a stranger.
Ms Clarke, 60, was born at Mauthausen camp in Nazi-run Austria in April 1945, three days before it was liberated.
Yet her mother, Anna Bergman, 88, may not have lived to deliver her daughter without the kindness of a stranger.
During a train journey that lasted three weeks, a farmer gave her a glass of milk that may have saved two lives.
The story of what happened that day has been passed down the family and Ms Clarke, who was brought up in Wales but now lives in Cambridgeshire, uses it when she gives talks on the Holocaust to school children up to 50 times a year.
Ms Bergman, who is Czech, was being transported across Europe by rail to Mauthausen, a slave labour camp with its own gas chambers.
Heavily pregnant, she was hungry and dehydrated when the train stopped for a while and she was allowed to get down and stand nearby.
Ms Clarke said: "There was one stranger who offered her a glass of milk when she was absolutely starved and weighed five stone and looked like a skeleton.
"It was when she was travelling. She was put on this coal truck. She was on that train for three weeks.
"The train stopped and when the farmer walked by, he saw her. He was just stunned at the condition she was in."
Children were victims of the Nazis' brutality as well as adults
The farmer offered Ms Bergman a glass of milk but, her daughter said, nearby was a Nazi officer guarding the train who had a whip.
But that day, even he may have played his part in saving lives.
Ms Clark said: "He raised this whip to shoulder height as if to beat my mother if she accepted the glass of milk, but he didn't. He didn't say anything he just lowered his arm and let her have the glass of milk.
"At that moment, he was also compassionate. She maintains that might have saved her life. Who knows, perhaps it did."
Ms Bergman eventually arrived at Mauthausen. It was the camp where Simon Wiesenthal, later to become a renowned Nazi-hunter, was also an inmate.
Anna Bergman still wonders if that glass of milk saved her life
Ms Clarke said: "My birthday is 29 April. Three days after that the American army liberated the camp."
Ms Clarke herself weighed 3lbs. She did not move and she did not cry as she was wrapped in newspaper to protect her from the cold.
Unknown to Ms Bergman, her husband, Bernd Mathau, had been killed by the Nazis at Auschwitz months earlier and her parents, siblings and cousins had all died in the Holocaust.
Ms Bergman married again, to another Czech national, who had escaped the Nazis on one of the last available trains in 1939 and then had joined the RAF. The family moved to Cardiff when Ms Clarke was three.
Ms Clarke said: "Individuals can make a difference. There were a lot of them who did resist, save people, were kind, during the war.
"We have to be grateful, we have to honour them."