They were the first responders to the first responders at the Pentagon.
"We served moms and dads and partners and kids, and aunts and uncles and neighbors, and flight attendants and their families, the fire fighters and anyone impacted by 9/11," says Stephanie Berkowitz, who directed the Survivors' Fund Project at Northern Virginia Family Service.
The agency worked with more than 1,000 people in the years after the attacks: firefighters haunted by flames; flight attendants afraid to fly; family members who couldn't eat, sleep or work. For many, it's an ongoing process.
"There's the expectation that one grieves and moves on. What we learned about 9/11 and the reality of the families that were impacted on that day is that you don't grieve and you move on," Berkowitz says. "You cope to the best of your ability and you hopefully learn how to integrate that loss into your life."
But milestones, such as the anniversary of 9/11, can be especially hard.
"For some on 911 they saw that little yellow daisy as they were walking down the street, and it might just be that every month they walk down the street and see a yellow daisy it doesn't mean anything," she says. "And then on September 11, it has that traumatic impact on them."
Her colleague, Meredith McKeen, says this is the time when survivors need to concentrate on their own needs. "It may be a totally normal day for people and that's totally fine," she says. "It may not for others. So what I would hope for everybody is that they're kind to themselves." She suggests reaching out to family members and friends, reading, or exercising.
Andrea Zych doesn't usually think about how working with survivors affected her, because she was focused on helping them. But she remains inspired by their strength. "I've always felt it was a small role I got to have in the recovery, and in my community," she says. "It always felt like an honor to work with 9/11 victims."
And she'll be thinking of them this weekend.