Monday, 4 August, marks the anniversary of Great Britain declaring war on Germany in 1914. British Prime Minister Herbert Asquith announced at 11 pm that Britain was to enter the war after Germany had violated Belgium neutrality. This poppy grew in the Tyne Cot Military Cemetery, in Passchendaele, Belgium, where an estimated 600,000 soldiers died in battle.Christopher Furlong/Getty ImagesA simple wooden memorial cross marks the field outside Ploegsteert Wood, Flanders, where British and German soldiers played football during the World War 1 Christmas Day truce in 1914.Christopher Furlong/Getty ImagesThe sun sets on the sculpture of the 'Brooding Soldier' a monument commemorating the Canadian First Division's part in the Second Battle of Ypres of World War I.Christopher Furlong/Getty ImagesA memorial cross inside the fortified Advanced Dressing Station, near Essex Farm Cemetery. The station is where Canadian doctor Lieutenant Colonel John McCrae treated wounded and composed In Flanders Fields after burying his friend, Lieutenant Alexis Helme.Christopher Furlong/Getty ImagesThe sun sets on the sculpture of the 'Brooding Soldier' a monument commemorating the Canadian First Division's part in the Second Battle of Ypres of World War I.Christopher Furlong/Getty ImagesThe Cross of Sacrifice at Tyne Cot Commonwealth War Graves Commission Memorial, was built on top of a German pill box in the centre of the cemetery, purportedly at the suggestion of King George V, who visited the cemetery in 1922 as it neared completion.Christopher Furlong/Getty ImagesRows of panels with the engraved names of missing soldiers at Tyne Cot Commonwealth War Graves Commission Memorial.Christopher Furlong/Getty ImagesA wind turbine now looks over the firing line inside the WWI Yorkshire Trench in Boezinge, Belgium.Christopher Furlong/Getty Images