Around 1500 people attended a ceremony in Monaghan when the President, Mary McAleese, unveiled a monument to mark the 30th anniversary of the Dublin-Monaghan Bombings.
President McAleese also met some of the families of the victims and a group of people who survived the attacks.
33 people were killed and 240 others were injured when four car bombs exploded almost simultaneously in Dublin city centre and in Monaghan on May the 17th, 1974.
