Hundreds of people held candles in a late night vigil outside Belfast City Hall on Monday night to mark the centenary of the outbreak of the First World War.
The city joined the nationwide Lights Out commemoration, which saw houses and buildings throughout the UK plunged into darkness at 10pm, with just a single light or candle burning for an hour.
Northern Ireland Secretary Theresa Villiers, First Minister Peter Robinson and Irish heritage minister Heather Humphreys were among those to lay wreaths at the cenotaph.
Earlier that evening a service was held at the Church of Ireland St Anne's Cathedral in the city centre, where the head of the Anglican church in Ireland said war must always represent the abject failure of humanity,
Archbishop of Armagh Dr Richard Clarke said commemoration of the First World War could not be spiritually separated from carnage in Gaza and other contemporary trouble spots.
He addressed the Belfast service marking Britain's declaration of hostilities against Germany. The Duke of York read a lesson and lit a candle.
Dr Clarke said: "War must always represent the abject failure of the human spirit and of humanity itself.
"It can never be other and we should never pretend it is other."
Young people lit five candles, each representing a year of the war. The Royal British Legion raised two standards and an act of remembrance was introduced by Dean of Belfast John Mann.
Dr Clarke said: "Without being guilty of the worst kind of religious escapism, we cannot spiritually separate the violence, the carnage and the suffering of the innocent that is under our gaze today - whether in Gaza, in Israel, in Syria, in Ukraine or in Iraq - from our memorialising of the beginnings of the First World War."
The church's construction began in 1899 and in 1924 its west front was designated a memorial to Northern Ireland men and women who died during the First World War.
Eight volumes of books in the cathedral record the names of those from across Ireland who fought and died during the 1914-18 war.
Dr Clarke said: "In the Great War we see heroism and cruelty standing side by side, we see cynical disillusionment and moral determination intertwining and we see hope and despair in equal measure and on every side.
"This was the first time that the weaponry of war could be fully industrialised and it was, also for the first time, that the phrase total war was coined to indicate that civilians were to be regarded as being as much part of the war as the military."
He said extinguishing lights throughout the UK, a reminder of words used to characterise the outbreak of war by then British foreign secretary Sir Edward Grey, was an appropriate memorial.
"But yet, as people of faith, we must be ready to set alongside it another message about light and darkness, that eternal truth of the Gospel.
"The light shines in the darkness, and the darkness has not overcome it."
Dealing with the legacy of past violence is an everyday issue in Northern Ireland.
Dr Clarke said it was easy to create monuments to hatred, painful to recognise beauty.
"Memorialising can be a crude, self-obsessive and vengeful thing - an empty shell of past hatreds that seeks to demonise an enemy forever - or it can become, with forbearance, integrity and true spiritual courage, a thing of beauty that can strive to radiate the glory and the presence of God."
DUP MP Jeffrey Donaldson read a poem written by the mother of a member of the Royal Irish Rifles, Private Ralph Adams, killed on the first day of the battle of the Somme in 1916.
Part of it said:
"For King and country well he stood,
Unknown to cowards' fears;
In the battle strife he shed his blood
With the Ulster Volunteers.
He volunteered as an Ulsterman,
What more could a subject do;
He fought for King and country,
And he died for the red, white and blue."
Further reading:First World War centenary: Why we must never forget the sacrifice of an entire generation