Cindy McGinty's grief was born on the morning of September 11, 2001, when two hijacked planes slammed into New York City's World Trade Centre, killing her husband Mike McGinty. Mike was on the 99th floor of the North Tower when American Airlines Flight 11 crashed into floors 93-99.
"People often say to me, 'Well, it's been 20 years.' But it never leaves you, it never leaves you," she said from her home in Bloomfield, Connecticut.
Cindy, now 64, recounts how she had to be strong for their children David and Daniel, who were 7 and 8 at the time.
"I had a lot of work to do to get them to be the adults that they are now," she said.
Daniel, now 28, recently got married and Cindy was sad that Mike did not live to see his son's wedding day.
"Mike was a great father and husband and he really could have used some words of wisdom from his dad, and he didn't get that," she said.
Cindy is now a board director for nonprofit organisation, 9/11 Day.
"What we want people to do is to do good deeds on that day in remembrance of everybody who lost their life and everybody who serves our country," she said. "It's a way of recreating the unity that we had in the moments after the terrible attacks."
'Lack of justice'
Kristen Breitweiser's 20-year battle with the US government started when her husband Ronald Breitweiser was killed, at the age of 39.
"My husband Ron was on the 94th floor of the second tower and he called me to say that he had just seen an explosion on the building next to him," Breitweiser said. "He had felt his cheek get warm and he was watching people fall or jump out the windows across from him.
"We said our I love you's and got off the phone and like three minutes later, I saw his building explode right where he had sat moments before."
In short order, Breitweiser, a lawyer, became a widow, activist and author.
"When you look at the record of 9/11 and you see the utter lack of justice for the 3,000 lives lost, it's deplorable," Breitweiser said. "There is just this utter lack of desire or demand for accountability, responsibility and justice. And I hope going forward that maybe at some point the 9/11 families will be given what we deserve, which is peace and closure."
Breitweiser is one of the 'Jersey Girls' widows from New Jersey who pressed officials in Washington for a public accounting of the attacks. She eventually channelled her frustration into a book, "Wake-Up Call: The Political Education of a 9/11 Widow."
The 20th anniversary of the attacks with her daughter will be remembered in the same way it always has, spending time alone in nature.
"It's where we feel closest to my husband and it's where we are able to find a modicum of peace."
In the aftermath of the September 11 attacks, 11-year-old twins Mike and Dan Friedman walked to firehouses and hospitals, handing out socks to firefighters and first responders.
The boys had just lost their 44-year-old father, Andrew Friedman, on the 92nd floor in the North Tower.
"He meant everything to us as a dad, as a husband, as a friend, coach, role model," he said. "And that feeling that we're never going to see him again, that was tough. That was really tough."
Lisa Friedman Clark, Andrew's widow, recounts how her husband had supported her through a cancer diagnosis and chemotherapy.
"The only thing Andy worried about in the world was me," she said. "He was just kind."
Dan said the idea for the family's sock company, Tall Order, was born on that Friday after the 9/11 attacks.
"These guys would come from all over... to go help out at Ground Zero and walk through the rubble," he said. "And their feet were getting dirty and sweaty and stinky. So they would always ask for clean and dry socks... things to help out with recovery efforts. So to us, socks have always represented hope for our family."
Mike and Dan will remember their father on the 20th anniversary in the way they do each year.
"We always go out to one of his favourite restaurants, Peter Luger's in Brooklyn, where we get together with some of his closest friends from growing up," Dan said. "We share stories. We eat great food... and we just have a good time and we try to keep it as positive as possible."