Beginning NY1's coverage of the 15th anniversary of 9/11, our Cheryl Wills visits the Medical Examiner's office for an update on the thousands of unidentified remains, and she speaks with some families who are still seeking closure.

On September 11, 2001, Lisa Luckett kissed her husband, Edward, goodbye as he left for another busy day of work as a partner at the bond brokerage firm Cantor Fitzgerald.

She had no idea it would be their last goodbye.

"It feels like 15 years, it feels like five minutes, and it feels like 100 years," Lisa Luckett said. "It really does, because there's been so much that's happened in that time. We've gone through a lot."

Lisa believes the 40-year-old New Jersey father of three was killed instantly when the plane hit One World Trade Center. His remains were never positively identified.

"But they're ashes are ashes, and we are all ashes to ashes and dust to dust, and again that kind of esoteric letting go of what we can't control — it worked for me," Lisa said.

A few years after the terrorist attacks, the city gave the Luckett family — and more than one thousand others — a token of remembrance, seen in the video above.

"It's the dirt and dust and everything from Ground Zero after they had done as much as they could to find people's remains," Lisa said. "And I was OK with that, and I had friends who had pieces found over the years and [got] three different things of three different times and [they asked] 'What I do? Do I reopen a grave?' So I feel like I was kind of spared, actually."

According to the Medical Examiner's office, of the 2,753 World Trade Center victims, 1,637 — 60 percent — were positively identified, but 1,113 are still a mystery to scientists.

"This is a personal mission because we were here on 9/11. We saw the towers collapse, we saw the people fleeing up 1st Ave. right in front of our buildings," said Dr. Barbara Sampson, the city's chief medical examiner.

"And we know the families; we've been working with them from the very beginning," she added.

The last new identification of a 9/11 victim was made in March 2015, but Sampson says all hope is not lost for families that are still waiting for word.

"We constantly keep up with the science, looking for new possibilities to try to bring closure for these remaining families," Sampson said.

Eileen Walsh lost her 27-year-old son, firefighter Michael Brennan, that day.

She anxiously waited years for word of a positive identification. She received four separate calls that fragments of his body were found.

"We waited almost, I say, eight years before we buried any of his remains," Eileen said.

As she waited, through tears, a community came together, and in 2008 they dedicated a lush garden in Long Island City, named after her hero son.

"We miss him terribly, so many years later, but the garden is an important part of this community," Noah Kaufman of LIC Roots said.

"It's gonna live forever," Eileen said about the garden. "This is a space of love and hope — that will continue."