The Royal British Legion first sold poppies in 1921.
They sold out almost straight away and raised more than £100,000 for the those who had been affected by the war.
In 1922 a factory was set up, where disabled soldiers were employed to make the poppies.
This factory is still running and produces millions of poppies every year.
What is the etiquette?
There is no definitive answer to this.
Some say the poppy should be worn from 31 October, while others say you should wear it in the 11 days leading up to Remembrance Day. Some believe you shouldn't wear one until after Bonfire Night.
The positioning of the poppy can also cause some confusion.
Many say the poppy should be worn on one's left to be close to the heart, as well as the side of military medals. Others say men should wear it on the left and women on the right, just like the Queen.
The Royal British Legion, however, told BBC: "There is no right or wrong way to wear a poppy. It is a matter of personal choice whether an individual chooses to wear a poppy and also how they choose to wear it.
"The best way to wear a poppy is to wear it with pride."
Wearing the poppy in the military
According to the Army, Royal Navy and RAF dress regulations, the standard fabric poppy supporting the Royal British Legion Poppy Appeal can be worn as a personal choice on all uniforms from the first day of the Poppy Appeal until Armistice Day.
The Ministry of Defence has confirmed that wearing the poppy, however, is not obligatory.
During the National Service of Remembrance at the Cenotaph on Remembrance Sunday, personnel on parade do not wear a poppy as it is not a part of their formal uniform.
The service Chiefs in attendance do.
Despite the original sentiment behind the poppy, in recent years many have started to question what it represents.
Some, including RAF veteran Harry Leslie Smith, believe the poppy has been misappropriated by politicians, who use it to justify conflicts.
I am against wearing of the poppy b/c it has been co-opted by politicians to justified our present wars on terror that are eroding democracy