Queen Elizabeth II was the reigning monarch of Great Britain for 70 years, making her the second longest reigning monarch in history. She has decades of service under her belt, and it's hard to imagine a monarchy without her at the helm. But "'he Firmament' - as the royal institution in Britain is called - has a plan in case the queen passes away, as well as an established line of succession for whoever takes the throne next.

What happens when the queen dies?

Politico reported full details of Operation London Bridge, the code name for the U.K. government's plan in the event of the queen's death in September 2021. From the time of the Queen's death to her funeral will be 10 days.

Immediately after:

Prime Minister Liz Truss and her cabinet will meet the queen's coffin at St. Pancras Station. Prince Charles, who is first in line to the throne and king at the time, will tour the United Kingdom the day before the queen's funeral.

Immediately after the Queen's death, the Prime Minister will be briefed by the Queen's private secretary. A number of the most senior ministers and officials will also be informed before the general public is informed via 'official notification' from the Palace.

Solemnly, the flags over Whitehall will be lowered to half mast. The Royal Family's website will change to a black page announcing the Queen's passing. The royal family will announce plans for her funeral, which Politico reports will take place 10 days after her death.

Prince Charles, now king, will give a speech at 6 p.m. that evening. A memorial service will be held that same night at St. Paul's Cathedral.

The first day after:

Charles will be proclaimed the new monarch. Parliamentary activity in Great Britain will be suspended for 10 days.

The second day after:

The prime minister will meet the queen's coffin. If the queen passes away in Balmoral, according to Politico, her body, if possible, will be sent I London by royal train. If that is not possible, the coffin will be sent by plane.

The third and fourth day:

King Charles will begin his tour of the United Kingdom.

On the fourth day, there will be a rehearsal of the procession of the Queen's casket from Buckingham Palace to the Palace of Westminster.

The fifth day after:

There will be a procession of the Queen's coffin from Buckingham Palace to the Palace of Westminster, ending with a service at Westminster Hall.

The sixth day until the day of the funeral:

The Queen's casket will remain at Westminster Palace for three days, and the public can visit and pay their respects.

On the 6th day there will be a rehearsal of the state funeral procession.

Other heads of state and dignitaries from abroad will attend the funeral. The day of the funeral, will be a Day of National Mourning, as agreed upon in advance by the prime minister and the queen. The day will be treated as a day off, but if it falls on an existing weekend or day off, no extra day will be given. Employers will not be required to give their employees the day off.

Funeral day:

The funeral will be held at Westminster Abbey, and there will be a two-minute silence at noon throughout the United Kingdom. A memorial service will be held at St. George's Chapel at Windsor Castle, and the queen will eventually be buried in King George VI's memorial chapel.

How old is the queen and how long did she rule?

Born on April 21, 1926, the queen was 96 years old. She ascended the throne in February 1952 and ruled the country for 70 years, making her the longest reigning monarch in British history. (She surpassed the record previously set by Queen Victoria.) She is also the second longest reigning monarch in world history, currently behind King Louis XIV of France, who reigned for over 72 years before dying in 1715.

Who are the queen's children and grandchildren?

The queen has four children. From eldest to youngest: Prince Charles, Princess Anne, Prince Andrew and Prince Edward.

She has eight grandchildren: Peter Phillips, Zara Tyndall, Prince William, Prince Harry, Princess Beatrice, Princess Eugenie, Lady Louise Windsor and James, Viscount Severn.

She also has 12 great-grandchildren: Savannah Phillips, Isla Phillips, Prince George, Mia Tindall, Princess Charlotte, Prince Louis, Lena Tindall, Archie Harrison Mountbatten-Windsor, August Philip Hawke Brooksbank, Lucas Philip Tindall, Lilibet 'Lili' Diana Mountbatten. Windsor and Sienna Elizabeth Mapelli Mozzi.

Who is next in line for the throne?

Prince Charles will ascend to the throne immediately after the death of his mother, Queen Elizabeth II.