Transcript for Remembering the survivors of Auschwitz 75 years later
today marks 75 years since the liberation of auschwitz. We have spent weeks documenting Americans who survived the holocaust, as they prepared to go back. And over the weekend, it was an honor and privilege to travel back with them. For some, their first trip and many told me, likely, their last. And what we saw when we got there. Tonight here, the children of auschwitz. 75 years later, the stories from inside this gate are no less haunting. The electric fences still standing. From one of the world's darkest times. When families and children were lined up, brought here by the Nazis. In this piece of video, some of the youngest faces, the survivors and we wanted to find them. My name is Tova Friedman. I was 5 1/2 when I arrived to auschwitz. My name is Michael Bornstein and I was 4 years old. I was 13 years old when my family and I arrived in auschwitz. I was 11 when I arrived in auschwitz. I'm Claire Heymann. I was 18 years old. My name is David marks. My name is Lois flamholz. I was 16 when we came to auschwitz. Reporter: For 75 years, they have quietly made new lives all over America, devoted to their jobs, to their families, to their history. More than 1.1 million people were killed by the Nazis in auschwitz. Nearly a million were Jews. This is me. I'm 6 1/2. Reporter: Tova is on the far left. You're pointing to your number, here. Yes. Reporter: Tova's mother, like so many others, tried to protect her daughter in the face of such evil. Your mother never lied to you? Never lied to me. From the very moment that I could understand, maybe it was 3 or 4 years old, she told me what's going on. Reporter: She was doing it protect you? She was doing it to protect me. In fact, when I see a German coming towards me, I am supposed to move to the side, give him right of way. "Never, never," she said to me, face a soldier, no eye continue don't look into his eyes." That's what she told me. Reporter: She remembers the day. What her parents said. We're going to auschwitz. The trains were waiting. The cattle cars were waiting. The Noe was impossible, the screaming of the people, crying. People knew where they were going. Reporter: And when they arrive at auschwitz, she steps off the train. Soon they are told to undress. Her mother, again, telling the truth. She said to me, "If we're not perfect," she pointed to the crematorium. There was smoke, and I knew what she meant. I got undressed and I remember, I'm saying to her, "How am I, mom? How do I look?" She says, "You look great." She said, "You will be okay." Reporter: Mother and daughter are separated. So few children survived, but the ones who did describe the same thing. Irene Weiss, on the far left, a scarf around her head. Her family brought in a cattle car, too. All of a sudden, the crowd moved and we were up. Reporter: Her family was Separation was, like, in ten seconds. My mother and two little boys were immediately sent one way and I suddenly realized that something very terrible happened to our family. Reporter: She would never see her mother again and she watched as women and children were sent to the gas chamber. The horrible, bloodcurdling screaming and praying and -- I blocked my years with my fingers because of the incredible anguish. And soon it was quiet and within a very short time, I could hear the train, the next train and the next train. We want to see, when are we going to see our mothers? We want to see our mothers. Reporter: Lois flamholz pleaded for her mother, too. She says, "Oh, you want to see your mothers? You see the smoke over there? That's where your mothers are." They all went to the right and they sent me to the left. I never saw the family again. It was everything in a rush. Each officer had a cane in his hand and he said, "Make it fast." It was shocking that, all of a sudden, you see that you are alone and just before, you were with your parents. I never cried. There was nobody to cry to. Reporter: Tova's tears were silent, too. And she remembers getting the tattoo. "What's your name?" I gave her my name. She says, "That's not your name anymore. Your name is 27,633." And she said, "You have to memorize it." If you don't answer to this, you'll be shot. Reporter: And to this day, you remember the number -- Yes. My number was a-6236. This is my number, a-17454. Reporter: Peter Somogyi remembers arriving too. He's on the left. He was a twin, which meant there was a new kind of horror. Dr. Josef mengele conducting experiments on the children. They would ask for twins. Kwing for twins. First, my mother didn't know what to say, so, she didn't say a word. Second time, different say a word. Third time, she said, yes, I do have twins, and immediately, two soldiers grabbed us and I had no chance -- even the slightest chance to say good-bye to my and that's the last time I saw her. Reporter: So few children were spared at auschwitz. They were too young to work and the Nazis did not want young witnesses. Tova remembers when it was her turn. I went to the crematorium. I remember. I didn't mind, because they gave us something delicious to eat in the morning and I hear my name and I said to myself, who knows my name? Must be my mother. Reporter: Her mother, separated months before, sees Tova through the fence. She asks, "Where are you going?" And I said, "To the crematorium" and they started screaming and I remember turning to the little girl next to me, and I said, "Why are they screaming? Every jewish child goes there, so now we're going there." Reporter: Tova arrives. Go down the steps and then you opened this door, and it's a gigantic room with a cement floor and all around are hooks, hooks with numbers. And this is the announcement -- get undressed. Look at the hook, the number that you're putting your clothes, because after you have the showers, you will find your clothes again." Reporter: But she remembers the chaos, the clipboards, the shouting that day, and suddenly, they order them to get dressed again. Something had gone wrong in the crematorium. She would walk back. And I hear my mother's voice again, my name. She says, "What happened?" And I remember saying it in a very loud voice, "They couldn't do it this time. They'll do it next time." Reporter: What the children did not know was that the soviets were closing in and so the Nazis began sending thousands on death marches. Those few who stayed behind, who found places to hide, survived. Tova was one of them and in that photo, on the right, Michael Bornstein, who was in the infirmary. He survived, too. Years later, they would meet, and he's about to turn the corner again. Nice to see you again. Reporter: Tova and Michael are going back to auschwitz. So is David marks, the carpenter so is Irene. Lois on the plane. I didn't want to go back at all, but this is something different. Reporter: And we wait for them in auschwitz. They slowly make their way through that gate and they walk proud. Reporter: Tova. Oh, hi. Reporter: And Tova puts words to why they have all come back. That we didn't forget them. That I remember the little girl going into the crematorium and she wouldn't come back, that I played with. Reporter: You remember them. We remember. That's what it is. We remember. Reporter: And there's David marks, who has never been back. But now, it's -- I'm getting in the fourth quarter of my life. Reporter: We are there with David, too. He lived in Barack 21 in auschwitz birkenau. He did not tell his own children. They never saw the tattoo? They never saw the tattoo until they were 12, 1 years old. Reporter: At 91, he now says, it's different. They should know what happened. They should know that -- never again. Reporter: And Tova, who bravely went inside the crematorium. She said it is important the next generation see this, too. And while inside, she offers the prayer for the dead. We should say a prayer for the dead. We should say a prayer for all these people who went in there. Reporter: And then, she asks her family to go in, too. Go inside. Go all the way. Reporter: Like so many of the survivors, Tova says she is here so that the world does not forget. The world needs to know -- The world needs to know and to be aware of this evil. To stop the evil before it spreads. And this is the -- this is the end of evil. Tova and so many of the survivors telling me that the world must keep their stories alive, to make sure this never happens again. That the world has to know. Tonight, we want to thank the memorial and museum for helping in this journey. And we have put links to their work on our "World news tonight" Facebook page. And we thank those survivors for sharing that are stories.
This transcript has been automatically generated and may not be 100% accurate.