FRANCE-BRITAIN-HISTORY-WWI-ANNIVERSARY-MEMORIAL

(From L) French President Francois Hollande, Britain's Prince William (Rear), Britain's Prime Minister David Cameron, Britain's Princess Catherine, Britain's Prince Charles and Britain's Prince Harry march towards the Thiepval Memorial on July 1, 2016 to attend a ceremony marking the 100th anniversary of the World War I battle at the River Somme, northern France. 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 / FRANCOIS NASCIMBENI (Photo credit should read FRANCOIS NASCIMBENI/AFP via Getty Images)