Now Isolated, Britain Joins France at WWI Centenary Event

One week after Britain's vote to leave the European Union, Prime Minister David Cameron and royal family members will stand side-by-side with France's president to celebrate their historic alliance at the centenary of the deadliest battle of the First World War.

More than 1 million people were killed, wounded or went missing in the Battle of the Somme, pitting British and French troops against German ones from July 1 to November 18, 1916, in northern France.

Cameron stressed Wednesday "the importance of keeping peace and security and stability on our continent" amid tensions and uncertainty after last week's vote.

Others at the event include Britain's Prince Charles, his son Prince William and their wives, Prince Harry, Irish President Michael D. Higgins, and former German President Horst Koehler.