Every year, the St. Louis Jewish Film Festival extends the festival experience with a later bonus film.

This year, the film is the poignant, remarkable documentary “Kinderblock 66: Return to Buchenwald.”

In 1944, as it became clear that Germany was losing the war, the Nazis started closing extermination camps and moving many prisoners, often by forced death marches, to Buchenwald. The camp in Germany held political prisoners and others, like Gypsies and gays, deemed “undesirable” by the Nazis, as well as Jews.

Among the inmates sent there were teenaged boys. As they arrived, the Communist Resistance members, who ran the camp’s daily operations under Nazi supervision, decided to gather the boys in a building at the back of the camp, far from close scrutiny by the SS, in a special section known as Kinderblock 66.

Years later, the now-aging survivors, the “boys” of Kinderblock 66, returned to Buchenwald as men, to commemorate the anniversary of the camp’s liberation. This film recounts their experiences, and includes the acts of unsung heroes, like a non-Jewish Czech Communist named Antonin Kalina, who was in charge of the barracks and whose actions likely saved nearly 1,000 boys.

“Kinderblock 66” focuses on the story of four of those “boys:” Pavel Kohn, Israel Laszlo Lazar, Naftali Furst and Alex Moskovic.

Moskovic and his son Steve, who is executive producer of the documentary, will attend the screening on Aug. 19 to speak about the film, along with another producer with a St. Louis connection.

“One of my producers, Brad Rothchild, is married to a woman named Michelle Sachar, and she comes from a prominent St. Louis family,” executive producer Steve Moskovic said, in a recent phone interview. “She’s actually the daughter of St. Louis-born historian Howard Sachar and he’s the son of the late Abram Sachar, who was the founding president of Brandeis University. And there is still a large contingent of her family there and they are all going to be at the screening.”

The screening is co-sponsored by the film festival, Dana and Troy Pohlman and the Holocaust Museum and Learning Center. “Troy Pohlman and his wife Dana made a generous donation to the production of the film, according to Moskovic.

The film is heartbreaking and inspiring, as well as beautifully shot and edited. Besides the eyewitness reports of “the boys,” the narrative presents careful research from historical consultant Kenneth Waltzer, professor or history and Michigan State University and director of its Jewish Studies Program.

The four “boys” in the film were born in different places and came from different Nazi camps before being sent to Buchenwald. Three of them, Furst, Kohn and Moskovic, were from various parts of Czechoslovakia, while Lazar was from Romania. They had been sent with their families to various concentration camps, Sered in Slovakia, Auschwitz-Birkenau and Theresienstadt. The youngest was thirteen. Some families survived, others did not.

Today, the Kinderblock 66 survivors live around the globe. Of these four, Furst and Lazar live in Israel, Moskovic in the United States and Kohn in Germany, to which he escaped from Czechoslovakia in 1967.

The film tells the story of these four survivors but also of Antonin Kalina, a political prisoner and Communist, who took charge of the boys’ care. The film reveals how his resourcefulness and courage helped ensure the boys’ survival. After the war, he disappeared behind the Communist Iron Curtain and was never properly recognized for his deeds.

Kalina has belatedly been nominated for the honor of being called Righteous Among The Nations. The filmmakers submitted his case in June 2011 to Yad Vadem, the international organization devoted to Shoah remembrance and education, which confers the recognition.

“Yad Vashem gets a lot of requests.” producer Moskovic said. “For most of the people, when you look at the Righteous — except for Oskar Schindler and maybe a handful of others like that – they are a man and a woman who saved maybe a child or a couple of children, you know, hid them in their home or adopted them somehow. Those are the people who are given the honor of Righteous. This is a pretty unique situation, where someone saved close to a thousand boys.”

The number saved rivals Schindler’s accomplishment, who is credited with saving between 1,100 and 1,200 Jews.

To involve the survivors directly in the filmmaking, director Rob Cohen gave the four men small, easy-to-use Flip cameras, so they could record their thoughts as a kind of video diary. The resulting footage gives the film an unexpected intimacy.

The film is narrated by actor Liev Schreiber. Initially, Moskovic and the other filmmakers wanted to make the film without narration but the complexity of the story and the history soon made it clear that a narrator was needed. Given how busy Schreiber is, Moskovic thought that getting him to do the narration might be difficult.

“So we sent the rough cut of the film to him, and I put a little note in there thanking him for his time and with my cell number. Two days later, my phone rings and it’s him,” Moskovic said. “He really liked the film, and he thought it was an important film, and he really wanted to do it.”