England's royal family traveled to Belgium Monday to commemorate the 100th anniversary of the battle of Passchendaele, or "The Battle of Mud", which caused more than 500,000 casualties for the Allied and Central powers.
Some 4,000 relatives of the soldiers who fought there gathered at the Tyne Cot Cemetery near Ypres, where almost 12,000 Commonwealth dead are buried.
The duke and duchess of Cambridge have taken part in Belgium for the commemorations on two days of the anniversary of the awful battle of Passchendaele.
Alongside the Duchess of Cambridge and Philippe and Mathilde, the King and Queen of the Belgians, the Prince and a crowd of more than 4,00 people watched as poppies fluttered from the rooftops at the Menin Gate.
The Menin Gate in the Belgian town is covered in the names of 54,391 British dead who have no known grave, Commonwealth War Graves Commission.
The heir-to-the-throne officially open the Zonnebeke Church Dugout, a preserved First World War dugout which forms part of the Memorial Museum Passchendaele.
During the service, attended by 200 descendents of those who fought, Prince William said: "Members of our families; our regiments; our nations; all sacrificed everything for the lives we live today". The duchess Catherine, who had opted for outfits clear the two days, as to bring light into these black memories, has laid a wreath.
They will hear the Last Post, which has been played at the gate by a bugler nearly every evening since 1928.
The British offensive was staged near Ypres from July 31 to November 10 1917, over fields of liquid mud.