Seventy-five years ago in 1939 when the Nazis invaded Poland, Renee Salt was just 10 years old. Now 85, she is able to look back and reflect on how, miraculously, she survived when so many others perished.
Renee's first experience of the Nazis was when they rolled into her home town of Zdunska Vola - throwing her and her family out of their home and appropriating all of their belongings. They were left with nothing and nowhere to go.
All of the Jewish people in town were forced into a ghetto - no one was allowed in or out and they weren't allowed to communicate with the outside world. They struggled to survive on starvation rations, with no sanitation and little access to any medicine.
The Nazis put up gallows in the communal outside space and regularly chose Jewish men at random to hang - leaving their bodies there for days - for all to see.
During the summer of 1942 everyone in the ghetto was rounded up for what Renee soon realised was a "selection". It was a process she was to go through numerous times.
The Nazis were choosing who would live and who would die - separating out the old, infirm and the young. She says the screams and cries were like nothing she had heard before as people begged for their children to be saved.
Renee's mother hid her two daughters underneath her coat but an SS officer grabbed Renee's eight-year-old sister and marched her away - this is the last memory Renee has of her sibling.
The selection process lasted for days and although Renee was a child, somehow she was spared. But out of 30,000 Jewish people in the ghetto only 1,200 were allowed to live.
They were sent in cattle transports to the Lodz Ghetto. They were forced to stand for the overnight journey, crammed in so tightly more than 100 people suffocated.
Every day, more and more Polish Jews arrived in the ghetto from across the country. They were regularly beaten by SS officers and many died from the cold, starvation or illness. Within two weeks of arriving at the ghetto, Renee's grandmother was taken away and killed.
In 1944, the Nazis told everyone in the ghetto they were being offered the opportunity to be relocated to somewhere they could work and be well-fed and looked after. Even though they didn't believe the Nazis, Renee's family had little choice
They were sent to Auschwitz Birkenau, the largest of the concentration camps. As soon as the train pulled up Renee says her father jumped down and with that he was gone.
No goodbye, no kiss, he simply vanished into thin air - an event she clearly still struggles to recall without breaking down.
Renee and her mother went through another selection process. They were sent to the left. Everyone who was sent to the right went straight to the gas chambers. She said the screaming from the gas chambers lasted for more than 15 minutes. In total more than a million Jews were murdered at Auschwitz.
Renee and her mother spent several weeks at the camp. They were then moved to Hamburg and eventually to another camp - Bergen Belsen. She describes the long walk of many miles from the train station to that camp - every step of the way she says was littered with dead bodies along the side of the road - prisoners who had collapsed and died en route.
As she walked through the gates of Bergen Belsen she told me of seeing a scene from hell; walking skeletons and bodies piled so high she couldn't see over the top. The camp was in chaos, the end of the war was clearly coming but Renee didn't think she would live to see it.
As she watched an allied tank approaching the gates she passed out. Several days later after coming round she found herself lying in a clean bed being washed and fed by German doctors and nurses who were ordered to look after their former prisoners.
Tragically, her mother died 12 days after the camp was liberated.
Renee says every day of those six years were spent living in fear. She never knew when there would be a selection or when a random act of evil would be inflicted upon her and her loved ones.
She says she has tried to make sense of what happened to her but simply cannot. These, she told me, were educated people who derived so much pleasure out of what they did.
After the liberation with nothing more than the clothes on her back, Renee made her way back to her home town in Poland. There she found an aunt who was one of the only members of her large extended family to survive.
They eventually moved to Paris where Renee met her husband - a British soldier who had in fact been one of those who had liberated Bergen Belsen. They were both so traumatised by their experiences they never talked about them, not with each other or to their children.
Twenty years ago when Renee was 65 she was persuaded she should do so, so that others could hear a first-hand account of the horrors of the Holocaust.
Although now old and frail and with memories still so terribly vivid, she continues to tell her story to schoolchildren. She says it is her duty and will carry on doing so as long as she can.