NEW YORK (PIX11) — Sunday marks 21 years since New York’s darkest day, when the terror attacks of September 11, 2001 claimed thousands of lives.

Among those killed was Jeff Goldflam, chief financial officer at Cantor Fitzgerald and father of then-high school student Ashley Bisman. Bisman joined PIX11 News on Tuesday ahead of the somber anniversary.

Now a New York City public school teacher with two children of her own, Bisman has also used the written word to tell the story of that day and its impact. She’s the author of the memoir “Chasing Butterflies,” and is also working on a children’s book, “September.” A portion of the proceeds of “September” will benefit the Tuesday’s Children nonprofit.

“That’s who I miss,” said Bisman, reminiscing on time with her father. “It’s not the businessman or the CFO. I just miss my dad.”

Watch the full interview in the video player above.