Queen Elizabeth II has died, Buckingham Palace has announced.
The beloved monarch first sat on the throne at the age of 25 70 years ago. Throughout her reign, she saw three generations grow up, visited around 150 countries, oversaw 15 UK prime ministers, won the hearts of the public, and powered through celebrations and scandals.
She was the epitome of strength; a woman who grew to be the nation's longest reigning sovereign, ascending to the throne at a time when women's capabilities were consistently overlooked.
For most of us, news of her death seemed like an unfathomable scenario - something that seemed as if it could never happen.
Unfortunately, the time came earlier today (September 8), when the beloved monarch sadly passed away at Balmoral at the age of 96. Buckingham Palace announced that Queen Elizabeth II passed away peacefully.
Following this news, the monarch's death has sparked a carefully coordinated series of plans put in place should the Queen ever pass away in Scotland, named Operation Unicorn.
While the full details have not been publicly announced, several snippets have made their way into the public forum.
Although some people may be familiar with the term 'Operation London Bridge', given Her Majesty's passing took place in Scotland, it is instead Operation Unicorn will take place at the same time.
In recent years, multiple news outlets - including The Independent, POLITICO, and The Scotsman - have obtained documents detailing the arduous processes that will reportedly be in place from the time Queen Elizabeth II passes away to the day of her funeral.
The Queen's ailing health in the months preceding her death sparked discussions as to how the United Kingdom would mourn her loss - with the documents, outlined by POLITICO, detailing the tremendous level of state action required to control unprecedented mourning and crowds following her passing.
The first step to this operation is 'D-Day', the day the Royal Family loses their monarch.
In the hours succeeding Queen Elizabeth's death, a "call cascade" will have already taken place - with the Prime Minister and other high-ranking government officials being notified via telephone of her death. After immediate family members have paid their respects, the Royal Household will then issue an official notice of her death to the public.
As Her Majesty passed in Scotland, Scottish Parliament will be suspended. Authorities will be given three days from the Queen's death to prepare for a motion of condolence in the chamber.
Ministers and senior civil servants will be notified of the death via email.
The Accession Council will meet to proclaim Charles the nation's new sovereign the day following the Queen's death.
Parliament will then have to agree on a message of condolence and discussion of all other parliamentary issues will be suspended for the next 10 days.
The Queen's body will likely be carried to Holyroodhouse Palace, then to St Gile's Cathedral in Edinburgh. It is expected that many people will pay their respects to Her Majesty at the Cathedral.
Following this, the Queen's coffin is expected to arrive at Buckingham Palace via Royal Train from Scotland. Operation Unicorn ends when the Queen leaves Scotland for the last time, triggering the remaining plans of Operation London Bridge. Both Operations will run parallel to each other.
Rehearsals will soon take place for Operation Lion - which is the procession of Queen Elizabeth II's coffin from Buckingham Palace to Westminster. The procession will be followed by a service in Westminster Hall where, for 3 days, the Queen's body will be in Westminster Hall for public viewing 23 hours a day - this is known as Operation Feather.
These few days are crucial as preparations for Queen Elizabeth II's funeral - held roughly 10 days after her passing - will be underway.
The Foreign Office, Home Office, and Department of Transport will be faced with the largest responsibilities: the Foreign Office will have to arrange for heads of state and VIPs to arrive, the Home Office will be tasked with managing security, and the Department of Transport will have to focus on resolving potential issues surrounding overcrowding in London.
It is possible that these days will be focused on creating alternative solutions to most services - including accommodation, hospitality, and healthcare - running at well over capacity.
The day of the state funeral, which will be held at Westminster Abbey, will be a Day of National Mourning. Across the UK, there will be a two-minute silence to commemorate the late monarch, and processions will occur in both London and Windsor.
Queen Elizabeth II will reportedly be laid to rest at the King George VI Memorial Chapel in Windsor Castle. And with that, the world sadly sees the end of a historic era.
Nevertheless, Queen Elizabeth II's legacy will continue to live on for generations following her death.