Former enemies united to mark the 100th anniversary of the start of World War I, with Belgium, France, Britain and Germany standing together in a spirit of reconciliation. Belgium's King Philippe and Queen Mathilde welcomed German President Joachim Gauck for a ceremony at the Cointe inter-allied memorial.

On Sunday, Gauck and French President Francois Hollande shared an intense hug during a remembrance ceremony in eastern France close to the German border.

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Prince William, Kate Middleton, French President Francois Hollande, Queen Mathilde of Belgium, her husband King Philippe and German President Joachim Gauck attend a WWI memorial service in Liege, Belgium(AFP)
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Prince William and Kate Middleton chat to French President Francois Hollande at the Cointe Inter-allied Memorial in Liege, Belgium, during a ceremony commemorating the 100th anniversary of the outbreak of World War I(Reuters)
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Veterans attend a ceremony at the Cointe Inter-allied Memorial in Liege, Belgium(Reuters)
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French President Francois Hollande and German President Joachim Gauck hug as they visit the crypt at the memorial to the battles at Hartmannswillerkopf, near Cernay, France(Getty)

Events were held around the UK to mark the centenary of Britain's entry into the First World War.

Prince Charles, David Cameron, Ed Miliband and Alex Salmond attended a wreath-laying ceremony in Glasgow.

Prince Harry led a march on the route servicemen took along the Leas to Folkestone harbour on their way to war. He also unveiled a steel memorial arch.

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People wearing First World War uniforms stand under a shower of a million poppies representing the dead, at the Tank Museum in Bovington, Dorset(Getty)
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Prince Charles and David Cameron attend a wreath-laying ceremony to commemorate the 100th anniversary of the outbreak of World War One, at the Cenotaph in Glasgow(Reuters)
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Deputy Prime Minister Nick Clegg, Labour leader Ed Miliband and Scotland's First Minister Alex Salmond lay wreaths at the cenotaph in Glasgow(Getty)
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Prince Harry speaks with members of the military during a ceremony to mark the 100th anniversary of the outbreak of World War One, in Folkestone, Kent(Reuters)
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A steel arch is unveiled by Prince Harry in Folkestone in memory of the estimated 10 million troops who passed through the town on their way to war(Getty)
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Volunteers continue to assemble an installation entitled Blood Swept Lands and Seas of Red by artist Paul Cummins, made up of 888,246 ceramic poppies in the moat of the Tower of London, to commemorate the First World War(Getty)
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A Chelsea Pensioner gives the thumbs-up as he is driven past Big Ben in an Edwardian-era car(Reuters)
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A man looks at the names of the dead at The National Memorial Arboretum near Lichfield, Staffordshire(Getty)