Prince William, Kate and Prince Harry travelled to France to attend the Somme Centenary commemorations. The royal trio attended a vigil on Thursday night, and will be joined by Prince Charles, the Duchess of Cornwall, and the Duke and Duchess of Gloucester for commemorations on Friday.
The battle of Somme took place on 1 July 1916 and is known as the deadliest battle in British history, with almost 20,000 British troops dead on the first day of the battle, which lasted 141 with more than a million killed, injured or missing from all sides by the end. The royal family are attending events across the Commonwealth to mark the battle's 100th anniversary.
Princes William and Kate attended a vigil at the Thiepval Memorial
William, Kate and Harry showed their respects by attending a vigil at the Thiepval Memorial on Thursday evening. The memorial commemorates British soldiers who died without graves and was lit up for the first time ever in honour of the occasion.
They looked moved as they heard of the one million dead (481,842 British and 250,000 French) in the largest and bloodiest battle of the First World War. Historian Glyn Prysor welcomed the royals to the site and showed them around the 45m (150ft) high memorial.
Kate looked elegant in a black Missoni coat
While Prince William and Prince Harry looked smart and sombre dressed in blue suits, Kate looked demure in a £850 Missoni coat and black dress.
The Duke and Duchess of Cambridge, both 34, and Prince Harry, 31, are not the only royals to attend commemorative events.
The Queen and Prince Philip remained in the UK to attend an evening vigil at Westminster Abbey, while Prince Andrew is due to attend the National Commemorative Service in Manchester on Friday. Princess Anne has travelled to Beaumont-Hamel Newfoundland in Canada to commemorate Canadian victims.