Queen Elizabeth II reached 70 years on the throne before the longest-serving monarch died aged 96.
Buckingham Palace said in a statement: “The Queen died peacefully at Balmoral this afternoon. The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow.”
Her eldest son Charles is now King.
He released a statement shortly after the death of his mother, saying: “We mourn profoundly the passing of a cherished Sovereign and a much-loved Mother."
As we pay tribute to the Queen's seven decades of service, here's a look back at the highs and lows of Britain's longest-reigning monarch.
The Queen ascended to the throne following the death of her father, King George VI, on February 6, 1952. During her time on the throne, she remarked on how much the world has changed in that time.
"As I look ahead with a sense of hope and optimism to the year of my Platinum Jubilee, I am reminded of how much we can be thankful for," she said in her official Platinum Jubilee statement earlier this year.
"These last seven decades have seen extraordinary progress socially, technologically and culturally that have benefitted us all; and I am confident that the future will offer similar opportunities to us and especially to the younger generations in the United Kingdom and throughout the Commonwealth."
Elizabeth and her husband, Philip, the Duke of Edinburgh, were in Kenya as part of their royal tour when news came her father had passed away in February 1952.
She was just 25 years old and a mother-of-two, but from that moment, Elizabeth became Queen of the UK and 15 Commonwealth realms, including Australia.
Her coronation was held the following year on June 2, 1953.
Elizabeth had to decide what surname she and her heirs would adopt, with House of Mountbatten (Philip's surname) and House of Edinburgh (after Philip's title) considered.
However, after insistence from her grandmother Queen Mary and the Prime Minister of the time, Winston Churchill, House of Windsor was kept.
This prompted the quip from Prince Philip: "I am the only man in the country not allowed to give his name to his own children."
One of the first difficult decisions Elizabeth had to make in the year of her coronation was whether to grant permission for her sister, Princess Margaret, to marry divorcee Peter Townsend, who was 16 years Margaret's senior.
She asked her sister to wait a year, but with the Church of England not permitting remarriage after divorce and politicians against the union, Margaret was left with the options of becoming a commoner or forgoing the marriage, which she eventually chose.
In 1977, Queen Elizabeth II not only celebrated her Silver Jubilee after 25 years on the throne, but also became a grandmother when Princess Anne gave birth to Peter Phillips in November.
The next couple of years were tumultuous for Her Majesty, as Princess Margaret divorced her husband Lord Snowden in 1978, and in 1979 her second cousin and close friend, Earl Mountbatten, was assassinated in Ireland.
In 1981, her heir and eldest child Prince Charles married Lady Diana Spencer in a ceremony that was watched by millions around the world.
But that year also saw two attempts on Queen Elizabeth's life.
The first was during the Trooping of the Colour when she was shot at six times at close range.
Luckily they were blanks, but the 17-year-old gunman was jailed for five years.
The second time was during her tour of New Zealand in October when another 17-year-old shot at her using a rifle but missed.
He was jailed for three years.
A final breach of The Queen's security happened the following year when she awoke to discover a man in her bedroom.
While her Ruby Jubilee year should have been one of joy, The Queen named it her annus horribilis.
Not only did Prince Andrew and his wife Sarah separate, and Princess Anne and Captain Mark Phillips divorced in the first half of 1992, but she was pelted with eggs during a state visit to Germany and a fire ripped through one of her main residences, Windsor Castle, in November.
The year finished off with Prince Charles and Princess Diana announcing their separation.
"1992 is not a year on which I shall look back with undiluted pleasure," she said in her Ruby Jubilee speech.
"In the words of one of my more sympathetic correspondents, it has turned out to be an 'annus horribilis'."
In 1997, Princess Diana died in a car accident in Paris and the public turned on the Royal family, seen as cold and uncaring over the loss of the people's princess.
In 2002, The Queen celebrated 50 years on the throne, however her Golden Jubilee was also marred with sadness.
Her sister Princess Margaret passed away in February and her mother, The Queen Mother, died in March.
In 2005, Prince Charles married Camilla Parker Bowles in a civil ceremony.
In 2010, Queen Elizabeth II became a great-grandmother when Savannah Phillips was born.
The following year Prince William married Kate Middleton in a royal wedding again watched by millions around the world.
The Queen's Diamond Jubilee in 2012 was a joyous year.
London hosted the Olympics, Kate and William announced they were expecting their first child and street parties were held up and down the UK to celebrate her 60 years on the throne.
In 2017, The Queen not only celebrated her Sapphire Jubilee but also 70 years of marriage to the Duke of Edinburgh.
2020 saw another bombshell for Her Majesty when Prince Harry and his new wife Meghan Markle announced they were quitting royal life and moving to North America.
Just after the shock announcement, the COVID pandemic hit.
In April 2021, The Queen's beloved husband Prince Philip passed away, aged 99.
While Prince Andrew said his mother was stoic in the face of her loss, he added: "She described it as having left a huge void in her life but we, the family, the ones that are close, are rallying round to make sure that we're there to support her."
As Her Majesty celebrated another jubilee earlier this year, she was noticeably more frail and had withdrawn considerably from official engagements.
However, she was never far from the public eye and the Royal Family released an official Platinum Jubilee portrait of the monarch.
The Queen also addressed the public in a personal message.
"Thank you to everyone who has been involved in convening communities, families, neighbours and friends to mark my Platinum Jubilee, in the United Kingdom and across the Commonwealth.
"I know that many happy memories will be created at these festive occasions," she said.
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