From Wikipedia:
Remembrance Day (also known as Poppy Day, Armistice Day or Veterans Day) is a memorial day observed in Commonwealth countries to remember the members of their armed forces who have died in the line of duty since World War I. This day, or alternative dates, are also recognized as special days for war remembrances in many non-Commonwealth countries. Remembrance Day is observed on 11 November to recall the official end of World War I on that date in 1918; hostilities formally ended “at the 11th hour of the 11th day of the 11th month” of 1918 with the German signing of the Armistice (“at the 11th hour” refers to the passing of the 11th hour, or 11:00 a.m.)
The day was specifically dedicated by King George V on 7 November 1919 as a day of remembrance of members of the armed forces who were killed during World War I.
The red remembrance poppy has become a familiar emblem of Remembrance Day due to the poem In Flanders Fields. These poppies bloomed across some of the worst battlefields of Flanders in World War I, their brilliant red colour an appropriate symbol for the blood spilled in the war
