The Rev. Anne O. Weatherholt, 50, was in a gym class when she heard the news of Kennedy's assassination.
She remembers her family watching the televised funeral services. She recalls her father, a veteran of World War II military service, standing at attention as the horse-drawn caisson carried the slain president. That was the only time she ever saw her father cry.
The assassinations of the president's brother Robert Kennedy and Martin Luther King Jr. followed a few years later.
Space Shuttle Challenger exploded during launch - live on broadcast television - in 1986.
A bomb ripped through the Alfred P. Murrah Federal Building in Oklahoma City in 1995.
Greg Harris and Dylan Klebold opened fire at Columbine High School in 1999.
In October 2000, two young seamen from Washington County were killed along with 15 shipmates in an attack on the USS Cole in Yemen.
Less than a year later, on Sept. 11, the World Trade Center and the Pentagon were attacked.
The Space Shuttle Columbia and its seven crew members were lost earlier this month.
The list of tragedies is etched in the heart and mind of America and its late 20th- and early 21st-century history.
"We mark time by these events," Weatherholt says.
How do people deal with public tragedy? How do people grieve?
"Identification is a critical factor in how we deal with public tragedy," says Kenneth J. Doka, senior consultant to the Hospice Foundation of America and professor of gerontology at The College of New Rochelle in New Rochelle, N.Y.
He notes that there has been a comparative lack of public memorialization following the recent space shuttle disaster. One of the assumptions of space travel is that you are taking a risk, he explains.
By contrast, we truly identified with the victims of the Sept. 11 attacks - people just going to work, Doka says.
"People are affected differently. People grieve differently," Doka says.
When public tragedy happens, you can't believe it, says Faye Altizer, director of bereavement and social services for Hospice of Washington County.
The media can help people come together after an event such as the Sept. 11 attacks or the Columbia explosion. But there can be too much coverage, Weatherholt says. Seeing the twin towers fall over and over and over was not helpful, and people needed to turn it off.
A common reaction to a public tragedy is for people to gather together. "People need to be with other people that feel as they do," Weatherholt says.
"Grief is pretty hard to do in isolation," Altizer says. "It should be expressed in some way, in memorial services, in art, in poetry."
The Vietnam Veterans Memorial in Washington, D.C., has been a source of healing for many, says Jon Radulovic, director of communications for Hospice Foundation of America.
People often gather in churches or other religious settings. Ritual, with familiar words, prayers and songs, is comforting and provides grounding, Weatherholt says.
An Episcopal priest, Weatherholt served as celebrant for the funeral service for USS Cole Seaman Apprentice Craig Bryan Wibberley in October 2000.
The 19-year-old Williamsport native was killed in the bombing of the Navy destroyer in the port of Aden in Yemen.
Weatherholt says the experience really changed her life. "The blast was a blast of hatred, but God has turned it for us into a wave of love," she said during the service.
State, local and military officials were present at the service, and people who never knew the young man stood along the highways to watch his casket pass by.
"That affected our community," Altizer says.
"It's important to recognize that different people deal with grief in different ways," Doka says.
A grievous loss, public or private, can make us feel more vulnerable, personally, Altizer says. Grief can serve as a reminder of just how precious and fragile life is.
Grief probably brings most of us closer to our spiritual core, Altizer says.
"That's a good thing," she says.
There are positive and negative reactions to public tragedy, Doka says.
It was a good thing that the 1941 attack on Pearl Harbor unified the country, Doka says. But in wanting to get back at the Japanese, Japanese-Americans were held in internment camps.
The key, in personal or public grief, is to assess what you are experiencing and to give it some sort of expression, Doka says.