Queen Elizabeth leads Britain's remembrance of WWI dead

LONDON -- Queen Elizabeth led Britain's observance of Remembrance Day on Sunday, honoring more than 800,000 service members who died during World War I. This happened as her grandson, Prince Harry, made a surprise trip back to Afghanistan.

A nation stood in silence.

From the tower of London and its spectacular sea of red 800,000 ceramic poppies honoring World War I dead to the memorial service where the queen laid a wreath at the foot of Britain's war monument.

She's taken these very steps every year for five decades.

But this year is especially poignant, marking a century since the start of World War I.

Queen Elizabeth observing Britain's Remembrance Day CBS News

It also comes at a time of unprecedented security after counterterrorism police arrested four men this week suspected of planning an attack on British soil. There were even reports that the queen herself might have been a target.

That threat did not deter Queen Elizabeth from duty, nor the thousands of spectators who stood for hours on crammed sidewalks.

The queen was joined by Prince Phillip, Prince Charles, and Prince William, all military veterans themselves. The only one missing was Prince Harry, who made a surprise return to Afghanistan, to pay his own personal respects for more than 450 British soldiers who lost their lives and where the Prince himself served two tours of duty.

The prince's visit to Afghanistan serves as a reminder of the conflicts Britain is still waging. Remembrance Sunday honors all of the country's war dead of the past 100 years. And tonight, images of poppies are falling from Big Ben in tribute to those British soldiers who fell in the line of duty.