Survivors and families of those killed in the Claudy bombings 50 years ago will later gather in the quiet village of Co Londonderry to mark the anniversary.
At the memorial in the village, a church service with readings and songs takes place across all parishes.
Nine people, Catholics and Protestants, were killed and 30 injured when three car bombs exploded in the village on July 31, 1972.
The victims included nine-year-old Kathryn Eakin, who had been cleaning the windows of her family’s grocery store, 15-year-old Patrick Connolly and 16-year-old William Temple.
The adults killed were Artie Hone (38), Joseph McCluskey (39), Elizabeth McElhinney (59), James McClelland (65), Rose McLaughlin (52) and David Miller (60).
The attack was blamed on the Provisional IRA, although the group has never claimed this.
Nobody was ever convicted for the attack.
Several of the bereaved families are continuing legal action against the Catholic Church after a 2010 report by the Police Ombudsman found that a Catholic priest, the late Father James Chesney, was a suspect.
According to the report, the police, the state and the Catholic Church have covered up his alleged role in the bombing.
Victims’ Group South East Fermanagh Foundation (SEFF) has supported families over the past 12 months to develop a range of projects and events to mark the anniversary.
Kenny Donaldson, Director of Services, said: “We have had a relationship with the Claudy families for a number of years but over the past 12 months we have worked with all nine of the bereaved, those injured, the churches, schools and a number of others at the Development of a series of events for the 50th anniversary.”
He added: “The Claudy bombings were an attack on the entire community in the area and it proved that nine innocent people died, young and elderly, male and female, Protestant and Catholic – these neighbors died together and Claudy became as a small village changed forever.
“The bereaved have shared their experiences of the past few months with an appointed project leader, culminating in the production of a publication to be released on the day of the anniversary.
“The schools have also developed a digital-based project where they work in partnership, looking at the past within Claudy, the present and her aspirations for the future.
“There will also be a community-based public service held on Sunday at the Claudy Memorial and in the main parking lot beginning at 3pm.”
SDLP East Derry MLA Cara Hunter said the impact of the Claudy bombing is still having a profound impact on the area 50 years later.
She said: “As the 50th anniversary of the Claudy bombing approaches, my thoughts are with the families of the victims and all those affected.
“The events of that time cast a dark shadow over this village that has persisted to this day.
“Several families and a community were torn apart as a result of this bombing, and for many the pain is as real today as it was when this shameful act was carried out.”