Hundreds of people have attended ceremonies in the North to mark Remembrance Sunday. Representatives of the US, Canadian and French governments were present at the commemoration at the Cenotaph at Belfast City Hall.
Dozens of wreaths were laid at the memorial and a two-minute silence was observed for the dead. A Stormont Minister of State, Mr Des Browne, was among those present. Wreaths were laid on behalf of a range of organisations including the St John Ambulance, Royal Mail and the Fire Authority of Northern Ireland.
In Enniskillen friends and relatives of those killed by an IRA bomb in 1987 marked the atrocity as well as remembering the dead of both World Wars.
In Britain events were led by Queen Elizabeth with two minutes' silence. Services took place across Britain and as far afield as the Falkland Islands, on the 20th anniversary of the conflict with Argentina.
That war was at the forefront of the commemorations, with Falklands veterans parading at the largest service, at the Cenotaph in Whitehall.
The Duke of York, a former Royal Navy helicopter pilot in the war, led commemorations in the south Atlantic.
Ms Sara Jones, whose late husband was awarded the Victoria Cross, said: "What's important on the 20th anniversary of the Falklands to those of us who lost loved ones is that the rest of the country remembers with us at this time and that the rest of the people have not forgotten."
Despite the driving rain and cold, it was Whitehall that drew the largest crowds for the traditional parade of former servicemen and women and the pomp and circumstance of the massed bands.
Security at the event, which comes just ahead of Armistice Day, was tight, with the estimated 10,000-strong crowd having to pass through metal detectors and have their property searched. Hundreds of police officers were also patrolling the streets of Westminster.
The security measures came amid heightened fears in recent days of a terrorist attack, following a warning by the British Home Secretary, Mr David Blunkett.
Joined at the Cenotaph by the Duke of Edinburgh, the Prince of Wales, the Princess Royal and the Duke of Kent, Queen Elizabeth laid the first wreath to the fallen at the monument.
The area in and around Whitehall fell silent at 11 a.m. precisely, to mark the exact time when the first World War armistice came into effect on November 11th, 1918.
A single cannon shot heralded the silence as Big Ben struck the hour nearby at the Palace of Westminster. Another single cannon shot ended the silence.
Ten buglers then sounded the Last Post before the queen placed her wreath at the foot of the monument.
After being called to attention as the queen and official delegates left the Cenotaph, veterans, many of whom were in wheelchairs or walked with sticks, marched past the crowd, which in some places was up to 10 deep, to respectful applause.