Families of the victims of Bloody Sunday sobbed after witnessing a powerful dramatisation of the horrific events of that day.
Around 450 relatives of the 13 men shot dead by members of the Parachute Regiment attended a special preview screening of the film Bloody Sunday.
Trauma counsellors were on hand to provide emotional support to those most deeply affected by the starkly realistic depiction of the events on January 30, 1972.
Liam Wray, whose 22-year-old brother Jim was shot dead on that fateful day, says it is a stunning critique of a nightmare that affected so many people.
"It was a very potent piece of film. It encompasses the reality of Bloody Sunday, the naivety, the despair and the tragic brutality. I think it will affect people deeply."
In one of the most chilling scenes of the film, Jim Wray is seen being finished off by a soldier as he lies semi-paralysed on the ground.
The filmmakers says this scene was based on three sworn testimonies given to the Saville Inquiry, currently investigating the events of Bloody Sunday.
"I hope that this will bring home the brutality and inhumanity of that day," added Mr Wray.
The film stars James Nesbitt as Ivan Cooper, the head of the Civil Rights movement and the city's MP at the time of the tragedy.
Written and directed by Paul Greengrass - who directed the Bafta award-winning The Murder of Stephen Lawrence - it follows the lives of a number of key individuals leading up to the civil rights march and the tumultuous events that followed.