Operation London Bridge was implemented following the tragic passing of Queen Elizabeth II and provides a comprehensive 10-day programme for the monarch's funeral (via CNN).
Long before the queen died, a strategy for her demise and the days that followed had been developed. Funeral plans have now been finalised.
The traditional period of mourning for the queen is currently being observed in the United Kingdom; it will end with her funeral. There will be processions in Edinburgh, London, and Windsor as part of her state funeral.
Her last resting site, St. George's Chapel at Windsor Castle, will then host the funeral.
While the public will not be let into the funeral, mourners may visit Queen Elizabeth's casket while she is lying in state (via the BBC).
Since the public can attend the Palace of Westminster and line up to pay their respects to the monarch, it is customary for this service to include a closed casket. This will continue up until her funeral on September 19 (Monday).
During her funeral, Queen Elizabeth's coffin will also be shut. Members of the royal family, according to Mental Floss, are interred in lead-lined coffins that remain closed throughout the burial to avoid deterioration.
For more than a year, these unique coffins can help preserve the body and slow down decomposition.