A Holocaust survivor who lives on the Upper West Side is finally telling his remarkable story of survival in the Auschwitz concentration camp -- a story he didn't begin to fully understand until he recognized himself in newsreel footage filmed when he was liberated. NY1's Michael Scotto has the story:

Michael Bornstein is reminded of the Holocaust when he looks at his arm.

"It's just part of me," he says. "I know I had considered taking it off before but chose not to."

The Nazis tattooed the ID number when he was imprisoned in Auschwitz.

For decades, he never wanted to talk about his time in the concentration camp where the Nazis killed 1.1 million people. But nearing his mid-70s, he decided to write about it with his daughter, Debbie Bornstein Holinstat.

"My father always felt really nervous about sharing his story — he was only four at liberation," she said.

"So, a lot of what he knows because relatives told him, and it's hard to talk about those things when you don't remember them so clearly." 

Bornstein's memory was jolted in the 1980s when he saw newsreel footage of children showing their Auschwitz tattoos as they were liberated by Soviet soldiers. He realized he was one of those children captured on film.

His father and brother had died in the camp. Bornstein, his grandmother, and his mother lived.

Rather than remain in their native Poland, Bornstein and what remained of his family eventually moved to New York after the war. He attended city public schools, went to college and earned a PhD. Raising his own family, he never wanted to look back.

"I would ask my dad, 'What was Auschwitz like? What was it like to be in a concentration camp? Holinstat recalled.

"And his answer was usually, 'Oh, Debbela, I don't remember. Why do you why want to talk about terrible things?'"

But with survivors dying, and his grandchildren growing up, Bornstein decided it was time to fully understand and tell his story.

Through Auschwitz documents kept in Israel, he learned that, ironically, he lived because he had been sick. The Nazis left him behind when they evacuated the camp as Soviet troops closed in.

"My grandmother Dora took me to the infirmary, and that basically saved my life because we could never have survived a death march," Bornstein said.

Bornstein, with the help of his daughter Debbie, turned his personal story into a book, Survivors Club.

He writes that of the Hundreds of thousands of children taken to Auschwitz. he was one of only 52 under the age of eight who lived.

Of the moment when Bornstein showed his tattoo to the troops who liberated the camp, he writes that the soldiers "pushed our arms aside, and asked for our names. We weren't prisoners anymore, we were survivors."

A story of survival that Bornstein only now fully knows.