Britain's Prince William (R) and his wife the Duchess Catherine of Cambridge (C) talk with young volunteers in the cemetery of the Thiepval Memorial as they attend the memorial ceremony on July 1, 2016, in Thiepval, during which Britain and France will mark the 100 years since soldiers emerged from their trenches to begin one of the bloodiest battles of World War I (WWI) at the River Somme. Under grey skies, unlike the clear sunny day that saw the biggest slaughter in British military history a century ago, the commemoration kicked off at the deep Lochnagar crater, created by the blast of mines placed under German positions two minutes before the attack began at 7:30 am on July 1, 1916. / AFP / POOL / Francois Mori (Photo credit should read FRANCOIS MORI/AFP/Getty Images)
