The Queen's coffin has made the long journey to London from Balmoral Castle in Scotland where she died last week ahead of her state funeral on Monday.
But as thousands watch the ceremonial procession unfold, many have taken to social media asking questions about the monarch's body inside the casket.
On Wednesday night (local time), the oak casket arrived at Westminster Hall where it will lie in state until her funeral at Westminster Abbey.
Despite hours-long queues of mourners lining up to pay their respect to the late Queen Elizabeth, a theory circulated online that her body isn't really in the coffin.
"Genuine question, with the Queen and her body, is it genuinely in that coffin?" one person asked on Facebook.
"I feel like it should be stored somewhere really cold or something or is it fine that she’s decomposing in the coffin being taken around?"
The Australian woman's post triggered comments from others asking the same question.
"I think the same!! Surely it’s empty?? So bizarre," one agreed.
"Omg I’ve been thinking this too," said another.
But it turns out there's a simple explanation, according to Ian Warren, an embalmer with Nelson Bros Funeral service, who said the Queen's remains were most likely embalmed.
What is embalming and why is it needed?
"By doing this, her body will be preserved and so not have to rely on refrigeration for several days to several weeks," he told Yahoo News.
Embalming refers to the process which restores the body, allowing it to be preserved for a longer period of time. Embalming chemicals, a fluid, is injected into the body through the arteries.
Not only is the process designed to create more life-like appearance by bringing colour back into the person's flesh, but it will also combat any bacteria or disease, Mr Warren explained.
Mr Warren pointed out this process is "quite common" and is "not unique to royalty".
It was used a lot over the past three years when Covid restrictions meant fewer people could attend funerals.
"We would embalm the person then hold them for maybe two weeks, three weeks to allow as many people as possible to attend the service rather than the 10 or 20 allowed with the restrictions," he explained.
It's also used when family members have to travel to attend the funeral of a loved one.
Why is the Queen buried in lead-lined coffin?
It's believed Queen Elizabeth's coffin, reportedly made over 30 years ago, is lined with lead which also helps to preserve the body for longer.
This is a royal tradition dating back hundreds of years, with Queen Elizabeth I, King Charles II and Princess Diana all being buried this way, according to Westminster Abbey records.
Lead-lined coffins are airtight, which means no moisture can creep in. This means some bodies can be preserved for up to a year.
"This is more related to being buried in a vault in the church or in a public building, like a crypt," Mr Warren explained, rather than those who are buried underground. And as for the royal family, it probably comes down to tradition, he said.
Doing this though "adds a considerable amount of weight" to the casket.
"That's why you would see a minimum of eight men carrying [the Queen] rather than say four or six which you might see with a normal funeral," he explained.
Where will the Queen be buried?
The late Monarch will be buried in the King George VI Memorial Chapel in Windsor Castle during a private committal service.
She will join King George VI and Queen Elizabeth the Queen Mother, and her sister Princess Margaret in the family tomb.
Once there, Prince Phillips' coffin will be transported from the Royal vault to join her in her final resting place.
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