(CNN) Rozalia Wolf was only 15 years old when the horror began. While most young girls worry about boys and homework, Rozalia Wolf spent her teenage days fearing she would not live to see the sun rise again. She spent a lifetime trying forget the horrors she had to endure at Auschwitz. This year she is turning 91 and for the first time she shares her story and tries to make sense of why she survived when so many others did not.
Rozalia was living with her family in Krakow when Adolf Hitler's troops marched into Poland in the fall of 1939. "Krakow was such a beautiful city before the Nazis came. One of the most beautiful places I have ever known", she remembers.
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Over seven decades later, Rozalia's memory is beginning to fade and she struggles to remember when exactly she was brought to Auschwitz, but she cannot forget the day she arrived at the death camp. "There were thousands of us, squeezed into wagons. Auschwitz was very close to Krakow, but they drove us around for hours, so we wouldn't know where we were'" she says.
"I remember it was dark, but it looked like the sky was on fire. It was so bright. It was the gas chambers, they made it look like the sky was burning," Rozalia remembers. The newly arrived prisoners had to take their clothes off and lie naked on the ground. Then the selection process started. Pregnant women, children, elderly people and anyone who was deemed unfit for intense physical labor were sent directly to the gas chambers.
"They told us to go left or right. One direction meant life, the other one meant death. I never knew which one I was going," the 90-year old says. Suddenly a colleague of her brother's was standing in front her. He was working at the camp. "He recognized me and brought me some food. All of a sudden I realized I was naked. I was so ashamed I dropped the food. Later, he asked one of the SS officers to give me a pair of underwear. You cannot imagine how cold it was. We were happy for every piece of clothing we were given."
The prisoners at Auschwitz were forced into excruciating physical labor, beaten, tortured and subjected to horrific medical experiments spearheaded by the SS Captain Dr. Joseph Mengele. Many of those who were not sent to the gas chambers died of starvation and illness. An estimated 1.3 million people were deported to the concentration camp and over 1.1 million were killed, out of which about 960,000 were Jews.
"We knew about the gas chambers. Every few minutes they sent people to die. I always wondered when it was going to be my turn, but I never gave up hope. Giving up meant you were going to die, but I wanted to live so badly," she recounts her days at Auschwitz. She says it was her incredibly strong instinct to live that helped her get through every day. "Even when they beat me I never cried. If they were going to kill me I did not want to give them the satisfaction of seeing me cry," she explains.
Looking back, Rozalia says it is hard to put the feelings into words. Prior to Auschwitz she was in a Krakow ghetto and the Plaszow concentration camp nearby, infamous for its sadistic treatment of prisoners. However, nothing compared to the horrors of Auschwitz, she recalls.
"One can talk about it and talk about it, but it is almost impossible to comprehend what a human being can endure and survive and what people can do to other people," she explains shaking her head in disbelief. "What kind of people are capable of doing this to other human beings? They must have had families and children themselves'" Rozalia still wonders today. "I think they forgot how to be human," she adds.
As allied forces started closing in on concentration camps in Easter Europe in 1944 and 1945, many prisoners were either killed or moved to concentration camps further West. In 1944, Rozalia was transported to Bergen-Belsen, a concentration camp near Hanover, Germany. Between 1944 and 1945 the number of prisoners at Bergen-Belsen tripled from around 7,300 to 22,000 according to the US Holocaust Memorial Museum. Many detainees were women, one of them was Rozalia, and another one was Anne Frank.
Bergen-Belsen became scene of sheer horror as the camp became increasingly overcrowded. Prisoners were starved for days, clean water was barely available and diseases started to spread killing tens of thousands in the beginning of 1945 alone. Yet Rozalia's story of survival continued. On April 15th, 1945, Rozalia's ordeal ultimately came to an end when British forces liberated the camp.
After the liberation, Rozalia first went back to Poland, then to Israel. In 1948 she moved to Germany. "My husband fell ill and the best treatment was there," she says to explain her move to the place that caused her so much pain in the past.
Rozalia lost her family and her youth in the Holocaust, but she never lost her will to live. "Maybe that is why I survived, I don't know. I was also very, very lucky. It was a miracle," she says. After the War she has tried not to think about what she had to go through. "Life goes on, you know", she says. Asked whether she would go back to see Auschwitz today, she said: "My grandchildren have visited the museum at Auschwitz. I wouldn't go back, I have already been there."