On 4 December 1971 , the Ulster Volunteer Force ( UVF ) , an Ulster loyalist paramilitary group , detonated Conflict.Attack.DetonateExplode a bomb at McGurk ' s Bar in Belfast , Northern Ireland . The pub was frequented by Irish Catholics / nationalists . The explosion Conflict.Attack.DetonateExplode caused the building to collapse ArtifactExistence.DamageDestroyDisableDismantle.Destroy , killing Life.Die.Unspecified fifteen Catholic civilians — including two children — and wounding Life.Injure.Unspecified seventeen more . It was the deadliest attack Conflict.Attack.Unspecified in Belfast during the Troubles .