LONDON -- Standing in the Tower of London moat alongside three generations of his family, David Woodrow stared out at a sea of red ceramic poppies and struggled to hold back the tears.

The poppy exhibition at the Tower of London has become a national sensation, with some 4 million people expected to have seen it by the time the last of the 888,246 poppies -- one for every Commonwealth soldier who died in the First World War -- is planted on Nov. 11, the day the war ended in 1918. The throngs of onlookers were so thick this past weekend that organizers asked visitors to postpone their trip.

While the Great War is not on the minds of many Americans, here it remains profoundly relevant. The government has pledged $80 million for four years of events to commemorate the centenary. There have already been numerous official and non-official events -- new books, plays, museum exhibitions, a massive “lights out” event -- but the popularity of the “Blood Swept Lands And Seas of Red” poppy installation stands out.

Since its royal opening in August, the installation has become a must-see on the tourist trail. At any given hour -- the artwork is floodlit at night -- onlookers are pressed against the black iron railings at the Tower of London peering down at the moat, many pausing in reflective silence before snapping photos: one of the most arresting images is of the “Weeping Window,” where poppies cascade out of a Yeoman Warder’s window, spilling out onto the moat like an ever-expanding river of blood.

The Internet is flooded with photos of the installation, with thousands of people uploading  pictures to Twitter -- as actress Joan Collins did on Wednesday -- and dedicated Facebook pages such as a “Tower of London Poppy Pictures and Selfies” page.

Adding to the spectacle, every day at dusk a speaker stands in the middle of the poppies and reads the names of 180 soldiers who died, followed by a cavalry trumpet call.

More than 18,000 people have volunteered to plant the poppies, including Woodrow, 78, a retired printer from Norwich who on a recent drizzly day planted poppies for four hours.

“My cousin, who was killed in  the First World War, was the same age as my grandson is now - that’s significant to me,” said Woodrow, who was wearing gardening gloves and pushing a metal stalk into the muddy ground.

Not everyone has praised the artwork. Jonathan Jones, an art critic for the Guardian, last week called it “a deeply aestheticised, prettified and toothless war memorial." He argued that a more appropriate memorial to mark the “horror” of war would be filling the moat with barbed wire and bones.

The following day, the British Prime Minister David Cameron stepped into the fray, telling the House of Commons that it was “a stunning display,” and “extremely poignant.”

What people do seem to agree on is that the commemoration is strikingly original, capitalizing on the particularly British knack for performance and pageantry. The Financial Times said it marked a shift from traditional memorials of the 20th century to “a very 21st-century blend of spectacle and 'edutainment'."

Following a public campaign to extend the life of the project, a spokeswoman for the Tower said Saturday that parts of the artwork would remain on display until the end of the month. On Nov. 12, volunteers will begin dismantling the hand-made poppies, all of which were snapped up by the public for $40 apiece (with a portion of the profits going to charities linked to the armed forces.)

The exhibition is the brainchild of Paul Cummins, a 37-year-old ceramic artist who literally suffered for his art during this project, losing his middle finger after his hand was crushed by a ceramic roller.

A few years ago he stumbled across a poem written by an unknown soldier who had died in the war. “And there was this line, 'The blood-swept lands and seas of red,'  and it sort of resonated in my head, and then I basically looked for a way to visualize it,” he said.

He pitched his idea to the caretakers of the Tower of London, a medieval castle on the banks of the River Thames that has its own long and bloody history. The Tower also has a significant connection to World War I as the place where over 1,600 recruits from the nearby financial district  -- they became known as the “stockbrokers battalion” -- were sworn in shortly after war broke out in 1914.

Tom Piper, a 49-year-old set designer with the Royal Shakespeare Company, was brought in to design the layout. He said his interpretation of Cummins’s idea was that the poppies should have “a very organic force that is almost like blood or the sea,” and that he wanted to engage with the Tower, not just simply plant poppies around its perimeter. And so poppies spill out of a window and climb up over walls, like soldiers surging over the top of a trench.

He said one of the reasons for its popularity has been that it has taken so long to install, with volunteers planting about 70,000 poppies a week.

“That illustrates, more than anything else, the horrors of war -- the fact that it has taken this long,” he said.

Some volunteers like Lesley Ryan, 64, a retired school teacher from south London, have come to the Tower on repeated occasions to help with the planting. She recalled how one ceramic poppy “just crumbled” in her hands. “It was so poignant,” she said, “because it reminded you that each one of these represents a fallen soldier.”

Britain's Queen Elizabeth joins British Prime Minister David Cameron at a ceremony to commemorate the war dead on Remembrance Sunday and places a wreath at the Cenotaph in Whitehall. (Reuters)