The Duke of Edinburgh attended a World War I memorial service in Sandringham to mark 100 years since Britain entered the conflict.
The Duke, 93, drove himself to the service at the St Mary Magdalene Church on Monday, which was led by Reader Sally Stanton.
Meanwhile, The Queen, attended a special service more than 400 miles away at Crathie Church near Balmoral, Scotland.
The Duke and Duchess of Cambridge, prince Harry and Prime Minister David Cameron attended a twilight ceremony at St Symphorien Military Cemetery, in Belgium.
Across Britain, people marked the solemn anniversary. The Lights Out campaign called for people to switch off lights for an hour. It was inspired by the words of wartime Foreign Secretary Sir Edward Grey, who said on the eve of the war: “The lamps are going out all over Europe, we shall not see them lit again in our lifetime.”