The Queen has led tributes to service personnel who have died while serving their country, at the annual service of remembrance at the Cenotaph in London.
After a two-minute silence, she laid a wreath, followed by other royals and the main political party leaders.
Prince Charles earlier paid tribute to British and Commonwealth forces who fought in World War II.
Around 10,000 ex-service personnel and civilians marched past the Cenotaph in parades to remember the fallen.
To mark the occasion, 20 war veterans used semaphore to send a silent message along the River Thames before it was decrypted at Whitehall.
Their line of communication began on the roof of the Royal Observatory at Greenwich and then passed along the Thames to Horseguards Parade.
The content of the message - "War turns us to stone. In remembrance we shine and rise to new days" - was laid on a wreath at the Cenotaph.
Air Chief Marshal Sir Jock Stirrup said people across the UK were honouring the debts paid by veterans and those who died.
"This day is not just about the Second and First World War, it's about the sacrifice and contribution by so many people over the years right up until the present day.
"The thing that always strikes me when this day comes round every year, is the way the whole nation rises to it", he said.
During the remembrance service, a selection of music was played by the Massed Bands of the Guards Division, the Pipes of the 1st Battalion Irish Guards, the Bands of the Royal Marines and the Royal Air Force.
Prime Minister Tony Blair and leader of the opposition Michael Howard also laid wreaths at the Cenotaph, alongside Liberal Democrats leader Charles Kennedy.
The remembrance was the first to include the Prince of Wales' new wife, the Duchess of Cornwall, who watched from the balcony of the Foreign Office with Prince William.
His brother Prince Harry marked the occasion at Sandhurst military academy.
One woman collapsed during the two-minute silence and had to be helped by police.
St. John Ambulance First Aiders were also in attendance at the event. They treated 28 people, sent eight to hospital and successfully defibrillated three casualties.
Representatives of a variety of faiths attended the event.
The two-minute silence was observed on the first stroke of 1100 GMT by Big Ben.
At the end of the silence, buglers of the Royal Marines sounded the Last Post.
The march-past, which included some veterans in wheelchairs and others walking with the aid of sticks, marked the end of the annual ceremony at the Cenotaph.
Taking part in the march-past was Britain's oldest war veteran Henry Allingham, 109, from Eastbourne, East Sussex.
The last survivor of the Battle of Jutland was with the Fleet Air Arm contingent and had an "emotional" day, said Dennis Goodwin, founder of the World War One Veterans' Association.
Spectator David Wilson, 43, and his wife Philippa who brought their son George, four and his five-year-old sister Martha, said the day was "very moving".
"We wanted to raise awareness for the children of the sacrifices other people have made for them," said Mr Wilson.
The Duchess of Cornwall watched alongside Prince William
The commemorative event took place as services were held across the UK to remember those killed in recent and past conflicts.
On Saturday, hundreds of ex-servicemen and women joined senior royals and the prime minister at the annual Festival of Remembrance, at London's Royal Albert Hall.
The Queen, the Prince of Wales, the Duchess of Cornwall and Princess Anne were among those present.
The event provided a mixture of entertainment - through performances by military bands - and solemn reflection.
It culminated in thousands of poppy petals being dropped from the roof of the hall to symbolise those killed in conflicts over the years.
In Liverpool on Sunday, a WWII-era Douglas Dakota airplane dropped 100,000 poppy petals over the city, while in Edinburgh wreaths were laid at the Stone of Remembrance outside the City Chambers.
In Glasgow, hundreds of people attended a commemoration and march by veterans.