Light beams and red poppies: London's WWI commemorations

Prince William, the Duchess of Cambridge, née Kate Middleton, and Prince Harry were in Belgium on Monday to commemorate WWI. Back in Britain, services were held across the country to remember the fallen in the Great War, and striking installations put in place in the capital to mark 100 years to the day since it began.

Scroll down to see striking photographs of the single light beam that penetrated the dark London sky as part of the national Lights Out campaign and artist Paul Cummins' installation of 888,246 ceramic poppies filling the dry moat of the Tower of London, which the British royals personally added to on Tuesday...

A single light beam pierces the London sky in an "hour of reflection" to commemorate the fallen of WWI, between 10pm and 11pm on Monday 4 August. Photo: © Rex

The national Lights Out campaign encouraged citizens to leave a single light on to mark the moment Prime Minister Herbert Asquith announced Britain had entered WWI at 11pm on 4 August 1914. Photo: © Rex

The Houses of Parliament were among the British landmarks propelled into darkness as part of the national Lights Out campaign in remembrance of those who gave their lives in WWI. A single purple beam penetrated the sky to mark an "hour of reflection" on Monday 4 August. Photo: © Rex

The single light beam originated in London's Victoria Gardens. The Lights Out campaign was inspired by foreign secretary of the time, Sir Edward Grey, who declared before Britain entered WWI: "The lamps are going out all over Europe; we shall not see them lit again in our lifetime." 

A spectacular installation of thousands of ceramic poppies is unveiled at one of London's most iconic landmarks, the Tower of London, to mark 100 years since the Great War began. Photo: © Rex

The installation by artist Paul Cummins, "Blood Swept Lands and Seas of Red", fills the dry moat of the Tower of London to commemorate 100 years since Britain entered WWI.  Photo: © Rex

Theatre stage designer Tom Piper was also involved in the striking installation, which will eventually total 888,246 poppies, each representing a life lost in the Great War. The last poppy will be added on 11 November 2014, Armistice Day. Photo: © Rex

The Duke and Duchess of Cambridge, along with Prince Harry, visit Paul Cummins' new ceramic poppy installation at the Tower of London. 

From 5 August, the official opening of the installation, each porcelain poppy will be available to buy for £25, with all proceeds going to military charities. Photo: © Rex