Survivors and families of those killed in the Claudy bombings 50 years ago will later gather in the quiet town of Co Londonderry to mark the anniversary.
An intercommunity service with readings and hymns will be held at the village memorial.
Nine people, Catholics and Protestants, were killed and 30 wounded when three car bombs exploded in the town on July 31, 1972.
The victims included nine-year-old Kathryn Eakin, who had been cleaning the windows of her family’s grocery business, 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 attributed to the Provisional IRA, although the group never claimed responsibility.
No one has been convicted of the attack.
Several of the grieving families are continuing legal action against the Catholic Church after a Police Ombudsman report in 2010 found that a Catholic priest, the late Father James Chesney, was suspected.
The report says that the police, the state and the Catholic Church covered up their alleged role in the bombing.
The South East Fermanagh Victims Group Foundation (SEFF) has been supporting families for the past 12 months in running a variety of projects and events designed to mark the anniversary.
Director of Services Kenny Donaldson said, “We have enjoyed a relationship with Claudy’s families for several years, but for the past 12 months we have worked collaboratively with the nine bereaved families, injured individuals, churches, schools and a variety of others. in the development of a series of events designed to mark a milestone in the anniversary of 50 years”.
He added: “The Claudy bombings were an attack on the entire community in the area and this was demonstrated by the death of nine innocent people, young and old, men and women, Protestants and Roman Catholics: these neighbors died together and Claudy as a small town. . was changed forever.
“Bereaved families have shared their experiences over the past few months with a designated project facilitator culminating in the production of a publication to be released on the anniversary day.
“The schools have also developed a project based on digital, working together in partnership looking at the past inside Claudy, the present and what they want for the future.
“There will also be a community-based public service taking place on Sunday at the Claudy Memorial and inside the main parking lot, beginning at 3 p.m.”
SDLP East Derry MLA Cara Hunter has said the impact of Claudy’s bombing still has a profound impact on the area after 50 years.
She said: “My thoughts are with the families of the victims and all those affected ahead of the 50th anniversary of the Claudy bombing.
“The events of that day have cast a dark shadow over this town that still remains to this day.
“As a result of this bombing, several families and a community were left shattered and for many the pain remains as real today as it was when this shameful act took place.”