The Queen will be given a state funeral - the first in the UK for more than half a century.
The last one was for wartime Prime Minister Sir Winston Churchill in 1965, while the last for a sovereign was for the Queen's father, George VI, in 1952.
But when and where will the Queen's funeral take place - and what do the plans involve?
When will the Queen's funeral take place?
The Queen's state funeral will take place on Monday 19 September.
The main service is at 11am in London, followed by a committal service at 4pm in Windsor and a private service at 7.30pm.
How was the date for the Queen's funeral chosen?
Under plans codenamed London Bridge, the Queen's funeral is to take place ten days after her death.
The day of death is known operationally as D-Day, or D+0, with the funeral held on D+10.
The Queen died on Thursday 8 September, which would traditionally have been D+0. However, because her death was announced late in the day - at around 6.30pm - plans have shifted by a day to allow time for the complex arrangements to be made.
Therefore, Friday 9 September is now considered D+0, which means the funeral will take place on Monday 19 September.
Where will the Queen's funeral be held and what are the exact timings?
The Queen's state funeral will take place at Westminster Abbey in central London, with the gates expected to open at 8am for the congregation to begin taking their seats.
Shortly after 10.30am, the Queen's coffin will be lifted from Westminster Hall for a grand military procession from the Palace of Westminster to Westminster Abbey.
As is traditional for a state funeral, the state gun carriage of the Royal Navy will carry the Queen's coffin. It has previously been used for the funerals of King Edward VII, King George V, King George VI, Winston Churchill, and Lord Louis Mountbatten.
The procession will set off at 10.44am from New Palace Yard, with the route taking in Parliament Square, Broad Sanctuary and the Sanctuary before arriving at Westminster Abbey at 10.52am.
King Charles and senior members of the royal family will follow the coffin, while military personnel will line the route.
The state funeral service will begin at 11am at Westminster Abbey, and will end at approximately 12 noon.
Towards the end of the service, the Last Post will sound, followed by a two-minute silence.
Reveille, the National Anthem and a lament played by the Queen’s Piper will bring the service to an end.
After the main service concludes at around noon, the Queen's coffin will be taken in procession from Westminster Abbey to Wellington Arch.
King Charles, the Princess Royal, the Duke of York, the Earl of Wessex, the Prince of Wales and the Duke of Sussex will follow behind the gun carriage.
The Queen Consort, Princess of Wales, Duchess of Sussex and Countess of Wessex will travel behind by royal car.
The route will take in some of London's major landmarks including Whitehall, Horse Guards, and The Mall.
The procession will arrive at Wellington Arch at 1pm, where the bearers will lift the coffin from the state gun carriage to the state hearse.
From there, the coffin will be taken to Windsor, where the hearse will travel in procession to St George's Chapel at Windsor Castle via the Long Walk.
A committal service will take place in St George's Chapel at 4pm and is expected to last for around 45 minutes.
At 7.30pm, the Queen will be buried at St George's Chapel's King George VI memorial chapel - an annexe to the main church - in a "deeply personal and private" family occasion, a spokesperson said.
The chapel is where her mother and father, King George VI, were buried, along with the ashes of her sister, Princess Margaret.
The Queen will be laid to rest with her late husband Prince Philip, Duke of Edinburgh.
Will the Queen's funeral be a bank holiday?
King Charles has approved an order that the day of the Queen's funeral will be a bank holiday in England, Wales, Northern Ireland, and Scotland.
The government decides on the period of national mourning, which has now started and will continue until the end of the day of the state funeral. This period of mourning, which usually lasts around 12 days, is not a public holiday.
Will the Queen's funeral be shown on television?
Both the 11am service at Westminster Abbey and 4pm committal service at St George's Chapel in Windsor will be televised.
However, the 7.30pm burial service is private and will be attended by family.
Will the public be allowed to line the route?
There will be a procession through London as the Queen's coffin is taken to and from Westminster Abbey, while in Windsor the coffin is expected to be driven through the town to St George's Chapel.
It is anticipated that crowds will gather along the route, but the finalised arrangements will take into account the current levels of coronavirus.
Will the Queen lie in state?
In keeping with tradition, the Queen will lie in state at Westminster Hall before the funeral, allowing members of the public to pay their respects.
This began on Wednesday 14 September, with the Queen lying in state for four clear days until the morning of the funeral on Monday 19 September.
Members of the public wishing to pay their respects will be admitted to Westminster Hall until 6:30am on the day of the funeral, before the doors close in preparation.
As the Queen died at Balmoral, there was also a second, smaller lying in state at St Giles' Cathedral in Edinburgh for the people of Scotland to honour her.
Who will be at the funeral?
Two thousand people, including world leaders and foreign royals, will gather inside Westminster Abbey on Monday, with US president Joe Biden among the first to confirm he will attend.
Many are expected to first gather at Royal Hospital Chelsea and travel collectively.
Among those who have been invited to attend the funeral are nearly 200 people recognised in the Queen's Birthday Honours, Downing Street has said.
Meanwhile, some 800 people, including members of the Queen's Household and Windsor estate staff, will attend the committal service afterwards at 4pm in St George's Chapel, Windsor Castle.
The evening burial service, conducted by the Dean of Windsor and attended by the King and royals, will remain entirely private, as a "deeply personal family occasion".
Can I leave flowers and cards?
Hundreds of bouquets, personal notes and candles have already started being laid in memory of Britain's longest-serving monarch.
Royal officials have issued guidance on where people should place their bouquets or other tributes.
Those who wish to leave flowers at Buckingham Palace will be guided to lay them at dedicated sites in Green Park or Hyde Park.
Flowers left outside the Palace gates will be moved to the Green Park Floral Tribute Garden by The Royal Parks.
At Windsor Castle, flowers can be left at Cambridge Gate on the Long Walk. These will be brought inside the castle each evening and placed on the castle chapter grass on the south side of St George's Chapel and Cambridge Drive.
At the Sandringham Estate, people are encouraged to leave tributes at the Norwich Gates.
For Balmoral Castle, flowers can be left at the main gate.
At the Palace of Holyroodhouse, people are encouraged to give tributes to the wardens at the entrance to the Queen's Gallery. Those flowers will be laid on the forecourt grass in front of the Palace's north turret.
Meanwhile at Hillsborough Castle, flowers may be laid on the castle forecourt in front of the main gates.
There will be further information from the Cabinet Office for at other public buildings, the Palace said.
People can also pay their respects by signing a book of condolence online. There are no physical books of condolences at the royal residences, but there will be an opportunity to sign one at various town halls and other locations throughout the UK.
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What is a state funeral?
A state funeral is a rare honour mostly reserved for the sovereign.
To the outsider, there is little difference between a state funeral and a ceremonial one. Both can include a lying in state - as the Queen Mother's did - and a military procession.
But at a state funeral, the gun carriage bearing the coffin is not pulled by horses. Instead, it is pulled by Royal Navy ratings - sailors - using ropes. This tradition began after Queen Victoria's funeral in 1901.
The only monarch not to be given a state funeral in the last 295 years was Edward VIII, who abdicated.
State funerals are the responsibility of the Earl Marshal and the College of Arms, and are publicly funded.
On rare occasions - by order of the monarch and by a vote in Parliament providing the funds - state funerals have been held for distinguished figures including Sir Isaac Newton, Lord Nelson, the Duke of Wellington, and Sir Winston Churchill.
The Duke of Edinburgh was given a ceremonial royal funeral - not a state funeral - in 2021, as was the Queen Mother in 2002.
Will shops and businesses be closed on the day of the funeral?
Companies are not required to close their doors, according to the national mourning guidance published on Friday 9 September.
It says: "There is no obligation on organisations to suspend business during the national mourning period.
"Depending on the nature and location of their business and the tone of planned events, some businesses may wish to consider closing or postponing events, especially on the day of the state funeral, however this is at the discretion of individual businesses."
Harrods is among the businesses to have confirmed it will close its doors on the day of the Queen's funeral.