With the death of Britain's Queen Elizabeth II, every detail of the next fortnight has been planned and rehearsed to the finest detail — and was even signed off by the monarch herself.
There have been regular meetings for decades between the many agencies involved, from central and local government departments to military and religious authorities and representatives of the other 14 countries where she was also head of state.
The Union Flag will be lowered on public buildings across the United Kingdom. The Royal Standard, which is the monarch's personal flag, is never lowered because the monarch never dies.
While many of the specifics are yet to be released, here's what we know right now.
King Charles III
Prince Charles automatically became King upon the death of his mother. He will be known as King Charles III. He is now head of state not just in the UK but in 14 other Commonwealth realms including Australia and Canada. He will also become head of the 56-member Commonwealth, although that is not a hereditary position, after his succession to the role was agreed by Commonwealth leaders at a meeting in London in 2018.
He has become head of the British Armed Forces, the judiciary and the civil service, and he is the Supreme Governor of the Church of England. He is the Fount of Honour, which means all honors, such as knighthoods, will now be given in his name.
Gun salutes and title changes
The Accession Council will meet at the 500-year-old St James's Palace in London. The Queen's death will be formally announced, and the new sovereign will be proclaimed.
The Garter King of Arms will read the Proclamation from the palace balcony and gun salutes will echo across the capital.
Prince William is now first in line to the throne.
There will be gun salutes across London — one round for every year of Elizabeth's life — and a broadcast by the new King will be played out.
Funeral arrangements
As monarch, Queen Elizabeth is automatically granted a publicly funded state funeral, and details will be released in the coming days. The Queen died at Balmoral Castle, her residence in Scotland, so over the coming days arrangements will be made for her to be transported back to England.
Read a more detailed rundown of next steps here.
CNN's David Wilkinson, Susannah Cullinane, Peter Wilkinson and Laura Smith-Spark contributed reporting to this post.