Remembrance Day is also referred to as Armistice Day or Poppy Day. It is a memorial day observed in the Commonwealth. Remembrance Day is a day of honouring members of the armed forces who have died in the line of duty.
Remembrance Day marks the day World War One ended, at the 11th hour of the 11th day of the 11th month, in 1918.
An annual two-minute silence is held at 11am to remember the people who have died in wars.
There is also Remembrance Sunday every year, which falls on the second Sunday in November, but in 2018 this aligns with November 11 itself.
On this day, there are usually ceremonies at war memorials, cenotaphs and churches throughout the country, as well as abroad.
READ MORE: How should you wear a poppy?
Remembrance Day 2018: Remembrance Day is also referred to as Armistice Day or Poppy Day
The Royal Family and top politicians gather at The Cenotaph in Whitehall, London, for a memorial service.
But while the day began after World War 1, it is used to remember all the people (and animals) who have died in wars.
This includes World War Two, the Falklands War, the Gulf War, and conflicts in Afghanistan and Iraq.
The Festival of Remembrance
This year, the Festival of Remembrance will take place on Saturday, November 10 at the Royal Albert Hall.
Remembrance Day: Prince Harry at the field of remembrance service at Westminster Abbey on Thursday
The event details say: “At the Festival of Remembrance this year, in the presence of The Royal Family, The Royal British Legion is leading the nation in saying Thank You to all who served, sacrificed and changed our world”
We can expect to see performances by Sir Tom Jones, Sheridan Smith, Sir Bryn Terfel, Tom Fletcher and Danny Jones, Sheku Kanneh-Mason and the Kingdom Choir.
The Central Band of the Royal Air Force and the Band of HM Royal Marines will also perform.
Palace officials said Prince Philip, Duke of Edinburgh will make his mind up on the day whether he plans to attend, but we will see the Queen, the Duke and Duchess of Cambridge and the Duke and Duchess of Sussex.
You can watch the Festival of Remembrance on BBC One at 8.30pm on Saturday night.
Remembrance Day 2018: The Royal Family and top politicians gather at The Cenotaph in Whitehall
Why do we hold a two-minute silence?
The first two-minute silence in Britain was held on 11 November 1919, when King George V asked the public to observe a silence at 11am.
This was one year after the end of World War One.
He made the request so "the thoughts of everyone may be concentrated on reverent remembrance of the glorious dead".
Why do we wear poppies?
The reason poppies are used to remember those who have given their lives in battle is because they are the flowers which grew on the battlefields after World War One ended.
This is described in the famous World War One poem In Flanders Fields.
Ever since then, they have come to be a symbol of remembering not just those who gave their lives in World War One, but all those who have died on behalf of their country.