Maureen Santora held a photograph of her son, Christopher, a New York City firefighter who responded to the World Trade Center, because she said she wanted him to be a part of the proceedings. When Mohammed offered to confess, she said she wanted to jump up and down with joy.
Another mother shared her recollection of the morning of the attacks with ABC News as she prepared to make the trip to Guantanamo.
Seven years ago on the morning of Sept. 11, the phone rang for Alice Hoagland.
"Mom, this is Mark Bingham," said the young man, giving his mother his full name. "I'm on a flight from Newark to San Francisco. There are three guys who've taken over the plane, and they say they have a bomb."
"You believe me, don't you, Mom?"
Bingham, a 31-year-old entrepreneur with a zest for rugby and adventure, was on United flight 93, headed home to a friend's wedding in California.
The phone went quiet. And then Hoagland said what would be among her last words to her only son: "Yes, Mark, I believe you."
On Sunday, Hoagland arrived at Guantanamo Bay to finally see the man who had orchestrated the attacks. She is among a group of victims and families chosen by a lottery to watch his military commission hearings.
"You'd have to be a very bloodthirsty and inhuman person to hatch such a plot," Hoagland told ABC News. "That's one reason why I'm glad I'm going to sit in the same room with Khalid Sheikh Mohammed and sort of take measure of that man, because he claims responsibility. He takes credit, if you will, for hatching that ugly plot."
The deadly impact of that plot shattered Hoagland's life.
"I still wake up nights startled by the fact that my only child is dead," she said. "They've taken the most precious thing out of my life. I'll never be the same."
Hoagland has made another life, as an advocate for the victims' families and for reform. In a way, she has moved on.
But she also remains very much back in that day, when she got that phone call from Bingham. She and other victims' family members have listened to the cockpit tapes, and she describes them in graphic detail -- the shouting and thunderous noises as Bingham and other passengers stormed the cockpit, the wind screaming over the plane's wings as it hurled to the ground.
And when she talks about that day, she relives it.
After Bingham's call to her the morning of Sept. 11 was cut off, Hoagland, desperate for information, began frantically calling "everybody we could think of." The FBI, United Airlines, the police.
She turned on the television, and she saw the horrific scene of the World Trade Center in flames. And then she saw the second plane hit.
"It was… it was the most horrible…," she said, her voice trailing off. "I thought, 'Is that Mark's plane?'" It turned out that it wasn't.
"Then we heard about the Pentagon being hit. Was that Mark's plane? And then they started announcing what flight numbers they were. United Airlines 175 into the South Tower. American Airlines flight 11 into the North Tower. American flight 77 into the Pentagon."
And then her sister-in-law frantically called her to the television: "Guys, they just mentioned Flight 93."
This is what Hoagland saw on the television screen: "They showed a panorama of the scene there outside of Shanksville, Pa., with hemlock trees afire and a huge, gaping hole covered over with some debris and emergency crews standing around, already."