Rememberance Sunday, a most special and important day to remember the start of the First WW in 1914 & the 70th anninversary of the D - Day landing in the Second WW and also the end of the war in Afghanistan.
This is to commemorate the "Fallen" and not forgetting the injured, something very SPECIAL for British and the Allied countries.

The remembrance poppy has been used since 1920 to commemorate soldiers who have died in war. They were first used in the US to commemorate soldiers who died inWorld War I (1914–1918). Today, they are mainly used in current and former Commonwealth states to commemorate their servicemen and women who have been killed since 1914. In those states, small artificial poppies are often worn on clothing on Remembrance Day/Armistice Day  (11 November) and in the weeks before it.