Christine Lee Hanson, a toddler who loved Mickey Mouse and making her family smile, was less than an hour into her first airplane ride, sitting with her mom and dad, when her father placed a call to his parents.
"Dad," Peter Hanson said over the phone, "I think we're being hijacked."
It was Sept. 11, 2001, and Peter, his wife, Sue Kim, and Christine, 2½, were going to California, where they planned to see relatives and go to Disneyland.
The family was aboard United Airlines Flight 175, the second plane to be hijacked. They were among the nearly 3,000 victims who died in the terrorist attacks; Christine was the youngest victim, one of eight children killed that day.
On Wednesday, several days before the 20th anniversary of the attacks, Christine's grandmother, Eunice Stylos Hanson, remembered her as "a really special little girl."
"She bubbled. She was so kind," Eunice told NBC News, recalling a time when she was recovering from foot surgery and Christine brought her a Band-Aid, thinking it would help. "If she did get into mischief, she found a way to make everyone laugh."
The last time Eunice had spoken to Christine was two nights earlier, when she called to wish the family a good trip.
Initially, the three were scheduled to fly out on Sept. 10. But they moved their flight at the last minute because Peter, a vice president of sales for a software company, had a work conflict, Eunice said. It's something that still haunts her.
"That killed me," she said. "For over a year, I couldn't talk about it."
Two decades of grief: 'I just got used to it'
Christine was born on Feb. 22, 1999, and lived with her parents in Groton, Massachusetts. She loved to help her father when he gardened, watering plants and trees and telling them that she was "feeding" them, Eunice said.
Christine was given her middle name after her grandfather, Eunice's husband, Lee Hanson. She and Lee had a bond from the start, Eunice said.
"She just clung to him when we went to visit," she said.
Eunice and Lee were close with their granddaughter, occasionally staying with her overnight when her parents were away. The next time they were going to see Christine was going to be shortly after her Disney vacation, at a friend's wedding. Eunice couldn't wait for Christine to show off her signature dance move, with her feet tapping and her body wiggling. Christine called it her "happy dance."
Peter's call on the morning of Sept. 11 came while Lee and Eunice were eating breakfast in their home in Easton, Connecticut. After receiving Peter's call, Lee called authorities, who informed him that a different plane had hit the World Trade Center in New York.
Lee and Eunice turned on the television and saw the burning tower. As the couple tried to process what they were seeing, Peter called again. This time, he told Lee that his plane was going to crash. "Don't worry," he told his father, later followed by "Oh, my God! Oh, my God! Oh, my God!"
Then, the line went dead.
"We had the television on at the time, and we saw the plane crash into the second tower," Eunice said. "Lee hung up the phone and he was never the same."
Lee did not live to see the Sept. 11 defendants go to trial; he died in November 2018. At 86 years old, Eunice is unsure whether she will, either, especially given the numerous delays in the case.
If she could, Eunice said, she would ask the defendants a simple question.
"After I got finished swearing at them, I would ask them, "How could you possibly have looked into my little granddaughter's eyes and want to kill her?'" she said. "How could you have so much hate?"
Today, Christine would have been 22, but Eunice still sees her as the energetic girl who carried a Peter Rabbit stuffed animal with her everywhere, a beloved possession that her grandparents donated to the 9/11 Memorial and Museum.
For 20 years, Eunice has thought of her on missed milestones: What would have been Christine's first day of kindergarten. When she would have graduated high school. When she would have gotten her first job out of college.
Eunice wonders if Christine would have followed in her mother's footsteps and pursued microbiology, or sales like her father, or something else entirely.
"You go through all these wonders," she said, "and then I get angry with those people that did this awful murder."
Christine was the second of the Hansons' three grandchildren, sandwiched in age between the two children of Eunice and Lee's daughter.
Having her daughter and other grandchildren has helped her get through the hardest moments, Eunice said, but has also served as a constant reminder of the pieces of their family that are missing.
Her grief has not lessened over the past two decades.
"I just got used to it," Eunice said. "I have become used to living with it."
When she thinks of Christine, Eunice said, she remembers how she always brought everyone joy. She said she had no doubt that she would still be doing the same today, had her life not been cut short.
"She was just a special little child," she said.