Sara Greenberg, 23

 Sara Greenberg grew up in a Conservative home in Philadelphia hearing the stories of how her mother’s parents survived the Holocaust. But the full impact of their experiences did not hit her until she joined many members of her family on a visit to her grandparents’ hometowns and death camps in 2005.

Someone brought a video camera along. “We didn’t go over there with the idea of creating a film,” says Greenberg, a 2009 graduate of Yale University who has deferred acceptance to Harvard Business School to work as a senior analyst for Thomson Reuters in Hong Kong.

Then, in her final term at Yale, she took a “Family and the Jewish Tradition” course. Instead of writing an essay, she decided to turn the 10 hours of recorded family memories into a mini-documentary. “I had to learn how to use the editing tools.” Her brother Jackson wrote an original musical score.

“B-2247: A Granddaughter’s Understanding” tells her grandparents’ story and delivers a message: the responsibility of the third generation — Greenberg’s — to preserve survivors’ legacies. While “B-2247” – the number tattooed on her grandfather’s left arm – features her grandparents’ words, it, unlike most Holocaust documentaries, emphasizes her “young perspective.”

“My generation is probably the last generation to be able to hear our grandparents’ survival stories firsthand,” she said at a speech at the UN last year.

Greenberg’s documentary, which received an A, has been shown at several film festivals, and has screened since 2009 at the UN’s annual Holocaust Remembrance Day ceremonies.

Since making the documentary, she has brought the film to the Anti-Defamation League’s Bearing Witness program for Catholic school educators, worked with Steven Spielberg’s USC Shoah Foundation to inspire other grandchildren of survivors, and shown the film in several New York and Philadelphia schools, mostly for non-Jewish audiences.

“It’s more,” she says, “than a fulltime job.”

Bearing witness in China: Based now in Hong Kong, she is helping to develop a Holocaust Museum and tolerance center there.