A cannon has been fired from a Northern Ireland wartime fortification to commemorate Britain's declaration of hostilities against Germany.
The ceremony took place at Grey Point Fort in Co Down, part of a network of coastal defences which guarded the mouth of Belfast Lough during the First World War.
It was decommissioned in 1956 and has been managed as a historical monument, one of several examples of defence heritage across the country.
Stormont Environment Minister Mark Durkan said: "These sites have direct and often poignant connections to past generations, whose lives were shaped and affected by conflicts that engulfed Europe."
The firing of the Vickers 6-inch bore gun at Helen's Bay, near Belfast, is one of a series of events taking place in the country to mark the centenary.
Historians have estimated that more than 200,000 Irish-born soldiers served in the British Army and Navy from 1914 to 1918.
Many from Northern Ireland enlisted in the 36th (Ulster) Division, which fought at the Battle of the Somme in July 1916. The division suffered 5,500 men killed, wounded or missing in two days of fighting.
Mr Durkan called for volunteers for a Defence Heritage Project to records sites of interest in Northern Ireland. These include structures from the First and Second World Wars and Cold War.
Plans, surveys and memories have already been shared and many sites given special protection.
The minister added: "Through public participation I hope there will be greater awareness of the rich legacy of heritage features that still survive, helping us understand the times past and protect them for future generations."