Starting on August 5 of this year, approximately the 100th anniversary of the entry of Britain into World War I, a British charity that runs a number of former royal castles has been planting ceramic poppies, the traditional Commonwealth remembrance symbol, in the moat of the Tower of London.

Today, on what Britons and Commonwealth citizens call Remembrance Day, the 888,246th poppy was planted — one for every British fatality in World War I.

Poppies, with their blood-red color, have apparently been associated with war and soldiers’ graves since the Napoleonic wars, but it was Canadian lieutenant colonel John McRae’s 1915 “In Flanders Fields” that cemented their symbolism and their association with the First World War.

Incidentally, the Tower of London was put to use a bit, grimly, from 1914 to 1918: Eleven of the spies Britain caught on its soil during the war, after being sentenced by a military tribunal, were held on the premises and then executed there.

For more on the Armistice and Remembrance Day, we’ve got a slideshow on the homepage.