What is lying in state and who receives the honor?
Queen Elizabeth II began lying in state on Wednesday and will continue to do so until her funeral on Monday morning. The queen is the first person in the U.K. to be honored this way in 20 years.
When someone lies in state, their coffin is placed in a viewing area so the public can pay their respects. In the U.K., a king or queen, a current or past queen consort and sometimes a former prime minister can lie in state ahead of their funerals.
In 2002, an estimated 200,000 paid their respects to the queen's mother, Queen Elizabeth the Queen Mother, as she was lying in state. She is the last member of Britain's royal family to do so, before Queen Elizabeth II this week.
Other notable monarchs who have received this honor are the queen's great-grandfather, King Edward VII, in 1910; the queen's grandfather, King George V, in 1936; the queen's father, King George VI, in 1952; and the queen's grandmother, Queen Mary, in 1953.
Prime Minister William Ewart Gladstone in 1898 and Prime Minister Sir Winston Churchill in 1965 have also had this honor.
The queen's mother and grandmother were technically queen consorts since they were married to kings. The current Queen Consort Camilla, who is married to the new King Charles III, would presumably lie in state as well.
Queen Elizabeth II's husband, Prince Philip, did not lie in state when he died last year because he is not a king. Although he was married to a queen, his title was prince.
In the United States, presidents and notable politicians can lie in state ahead of their funerals and most have been in the Capitol Rotunda.
A few non-politicians have received the distinction ahead of their funerals, and it is called lying in honor. Officer Brian D. Sicknick and Officer William F. Evans, who died from the January 6 attack on the U.S. Capitol, civil rights leader Rosa Parks and the Rev. Billy Graham have all received the honor.
In the U.K., the queen was honored in Scotland with a ceremony at Edinburgh's St. Giles' Cathedral, where she also lied in rest for 24 hours. The Royal Air Force carried her coffin to Buckingham Palace in London on Tuesday.
On Wednesday, during a large procession including the royal family, her coffin traveled from Buckingham Palace to the Palace of Westminster, where the public can pay their respects for five days, 24 hours a day.
The coffin rests on a raised platform in the middle of Westminster Hall, and each corner is guarded around the clock by units from the Sovereign's Bodyguard, Foot Guards or the Household Cavalry Mounted Regiment.
The coffin is closed on the platform, called a catafalque, and is draped in the Royal Standard flag. The Orb and Sceptre, which are part of the Crown Jewels and are used at the monarch's coronation, are also placed on top.
Visitors will be able to walk past the coffin to pay their respects but should expect long lines — possibly overnight, the U.K. government said. They will also have to go through airport-style security to get in.