Britain's Catherine (L), Duchess of Cambridge, Britain's Prince William, The Duke of Cambridge, King Philippe of Belgium and Queen Mathilde of Belgium attend an event that creatively tells the story of the four years of war on the Ypres Salient, in Market Square in Ypres, part of the commemoration for the centenary of Passchendaele, the third battle of Ypres on July 30, 2017. 
The battle of Passchendaele, also called the third battle of Ypres, took place between July 31 and November 6, 1917 in Passendale, West Flanders. / AFP PHOTO / POOL / Nicolas MAETERLINCK        (Photo credit should read NICOLAS MAETERLINCK/AFP/Getty Images)