The Duke of Cambridge has shared a traditional Maori greeting as he met the families of World War I New Zealand servicemen.
Prince William joined Princess Astrid of Belgium in commemorating the sacrifices of Kiwi soldiers who fought and died at Passchendaele.
The Duke and Princess were greeted by the Maori cultural group of the New Zealand Defence Force, whose spiritual calls and chants rang out across the white headstones, before they were led to their seats, The Telegraph UK reports.
William also shared a hongi with Victoria Cross-recipient Willie Apiata.
Representing the Queen, the Duke walked with the Princess past hundreds of headstones in a Commonwealth War Graves cemetery where thousands of Allied servicemen are remembered or buried.
The Duke told descendants of New Zealand soldiers that, although we may never truly understand the conditions they endured "we can remember".
He said that newsreels might have described them as ordinary men and women, but "there was nothing ordinary about their service or their sacrifice".
The Duke and Princess were the final guests to arrive for the service at Tyne Cot cemetery, near the town of Ypres in Flanders, held to mark the centenary of the Battle of Passchendaele.
October 12, 1917, has become known as the darkest day of the war for the New Zealand Division, which suffered heavy losses when they were ordered to take an area called Bellevue Spur but were bogged down in shell holes under enemy fire.
More than 840 Kiwis were killed fighting in a foreign land far from home - part of a huge toll of dead and injured both sides suffered that summer.
The Duke said: "As we have heard, October 12th 1917 was the 'darkest day' in the military history of a proud and committed people.
"For New Zealanders, the loss of more than 840 men in just a few hours is seared into the national consciousness. All told, the Battle of Passchendaele would claim close to 2000 - a devastating toll for a country with a population of just over a million.
"Half a world away, news of the losses was felt like a shockwave. Every death here left a shattered family there. Entire communities were robbed of their young people. No part of New Zealand was untouched by loss."
David Carter, speaker of the New Zealand House of Representatives, earlier told how Kiwi soldiers described devastating scenes amid a "porridge of mud" and "a place that stamps itself on one's mind and memory - like a red iron".
William went on to say: "The fight in these fields was of a magnitude and ferocity that is difficult for us, today, to fully comprehend. But while we may never truly understand, we can remember."
Tyne Cot cemetery is the largest Commonwealth burial ground in the world, with more than 11,000 servicemen buried there and tens of thousands more Allied fighters, whose remains have never been found, commemorated at the site.