The story of teenage diarist Anne Frank is known across the world. But a new survey suggests a “disturbing” lack of awareness about the Holocaust in the Netherlands, where she and her family hid for years before being discovered and deported to a Nazi concentration camp.

A Dutch Holocaust survivor and Jewish cultural leaders have expressed dismay at the survey, which was released Wednesday and suggests that more than half of the residents were not aware of the deportation and murder of Jews from the country during World War II.

The survey, conducted and released by the New York-based nonprofit Claims Conference ahead of International Holocaust Memorial Day on Friday, found that 53% of the respondents couldn’t identify the Netherlands as a country where the events of the Holocaust happened — rising to 60% among millennial and Gen Z respondents, meaning those under 40.

Historians estimate more than 70% of the Netherlands’ prewar Jewish population was killed during the Holocaust, more than 100,000 in total. Frank hid in a secret room in Amsterdam with her family from 1942 to 1944 before she died at the Bergen-Belsen concentration camp weeks before its liberation.

Despite widely available evidence of the systematic slaughter of 6 million Jews, 12% of those surveyed told te researchers either that the Holocaust was a myth or that the number of deaths was greatly exaggerated — the highest figure for any of the six nations surveyed in recent years. For the Netherlands, this rises to 23% of people under 40.

Previous Claims Conference research found that 15% of young Americans also doubted the historical record of the Holocaust.

“Survey after survey, we continue to witness a decline in Holocaust knowledge and awareness. Equally disturbing is the trend toward Holocaust denial and distortion,” Claims Conference President Gideon Taylor said in a press release accompanying the survey.

“It was disturbing to see a large number of my countrymen, from whatever religion they are, do not know enough about the Holocaust. Some of them, a small part, do not even know about the Holocaust,” Dutch Holocaust survivor Max Arpels Lezer, 86, told NBC News by video call from his home in Amsterdam.

After Jews began to be deported from the Netherlands, Lezer was sent from Amsterdam at the age of 6 to live with a foster family in the rural region of Friesland in the country’s north. He lived there with Ype and Boukje Wetterauw for six years and was never betrayed by the people of the village, where he stood out with his black hair and unusual name. The Wetterauws’ only child had previously died in infancy.

Today, Lezer has warm memories of an otherwise dark time. He remained close to the Wetterauws until they died and was named in their will. “I really was their son,” he said.

A wooden horse and cart that he played with alongside his foster brother, Gerrit, is now in the United States Holocaust Memorial Museum in Washington. Lezer spent years searching for his foster sister, Joke, who briefly lived with the family, without success.

Many other children who went into hiding, such as Anne Frank, were not so fortunate, as he has told countless classes of children over the years.

“When you sit in front of a class and you have students sitting on their stools, they hear there’s a guy coming in talking about the Holocaust and everybody does this and starts snoring,” he said, slumping back in his chair and closing his eyes.

“When you lived through the Holocaust, it takes a lot of courage to continue this kind of work. Maybe in other countries this attitude is different, but I happen to live here.”

A ‘red flag’ for education

Emile Schrijver, the general director of the Jewish Cultural Quarter in Amsterdam, said in an interview the survey results should act as a “red flag” for how schools deal with the Holocaust.

“That a third of young people feel that this may never have happened, that the numbers are wrong, that is shocking. The answer is clear, there is only one practical response: education, education and education,” he said.

Schrijver pointed out that during protests against the Netherlands’ strict social gathering rules when the Covid pandemic broke out, some protesters wore yellow stars to mimic the badges Jews were forced to wear in Nazi-occupied countries, in an attempt to illustrate state persecution.

“We have a society in which conspiracy theories are considered normal, in which people wore yellow stars during Covid protests, which a lot of people seemed not to object to. The stunning fact is not that people do that, there will always be idiots, it’s that people didn’t object to it,” said Schrijver, who is working on the new National Holocaust Museum, due to open in Amsterdam in September.

While pointing out that Amsterdam Mayor Femke Halsema did condemn the protesters wearing yellow stars, Schrijver said national politicians were much slower.

The Netherlands played a relatively small role in Holocaust history, but one that’s important in understanding the full story, said historian Anna Hájková, from the University of Warwick in England.

“In the context of Western Europe, disproportionately many Dutch Jews were caught and deported. On top of that disproportionately many Jews from the Netherlands who were deported died,” she said.

Hájková’s work has shown that about 70% of the Netherlands’ Jews, 100,657 people, were deported from the Netherlands, between July 1942 and September 1944 — 57,552 of whom were sent to Auschwitz. Only 854 returned, a very low survival rate compared to other countries.

“So the Netherlands, for a normal person who reads the newspaper, they might not know why the Netherlands is special. But for us as Holocaust historians, when you pay attention to the detail, it is remarkable,” Hájková said. 

The prospect of terror was never too far away. 

A man — the father of a friend, who was a Nazi collaborator — confronted Lezer as he and his friends walked to the seaside. 

“It wasn’t a real uniform but something like it anyway, with black shining boots,” Lezer remembered of what the man was wearing. “He looked at every child and he said to me: ‘I know you are a Jew-boy, we will come to get you.’ And he pointed his finger at my chest and I was so afraid I fell backwards onto the floor. My clothes became dark-blue between my legs.”

Lezer’s mother died at Auschwitz but he was reunited with his father in 1948. Lezer thought at first that his stepmother was his birth mother, but later learned the truth from a member of Amsterdam’s Jewish congregation. He says he suffered physical and emotional abuse at the hands of his stepmother, memories that are still hard to relive after all this time, and three times ran away back to be with the Wetterauws, once cycling for 12 hours to get there.

In 1961, Lezer married Sofia, now 86, who as a child had been hidden by a Dutch family during the war.

Lezer says it is imperative that the story of the Holocaust should never be allowed to fade from memory.

“Because if you don’t know enough about the Holocaust and you do not know that so many people died because of the Nazi persecution,” he said, “then you do not know enough to be realistic about the future.”