Members of the public were paying their respects to the late monarch from 5pm on Wednesday after her coffin was taken to the hall from Buckingham Palace.
Thousands from across the UK and the world queued up for hours to see the coffin, some arriving as early as Monday to get in line on Albert Embankment.
The largely black-clad crowd were solemn and pensive as they began to flow into the ancient hall where chandeliers and spotlights illuminated the scene beneath the medieval timber roof.
As hundreds of ordinary people of all ages filed past the coffin of the long-reigning monarch, many wiped their eyes with tissues.
Some bowed, some curtsied and some simply took a moment to look at the extraordinary scene.
Penny Purnell, aged over 65, from Littlehampton, West Sussex, said seeing the Queen lying in state drove home that she “really has gone”, adding: “That was quite hard to take.”
Ms Purnell and her friend Jill Scudamore, also aged over 65, joined the queue at about 11am on Wednesday and waited six hours to pay their respects.
Ms Purnell described the “grandeur” of the hall and the atmosphere as “very moving” as she spoke to the PA news agency afterwards.
On whether the pair said a silent farewell, Ms Purnell said: “It was just the thoughts in our head of appreciating her really. I didn’t really want to say goodbye, so I didn’t.”
Ms Scudamore said: “If anyone is willing to take the time to join the queue it is well worth the wait.”
Amma, in her 50s, from south London, said she broke down in tears as she paid her respects to the Queen.
Speaking to PA, she said she had been a fan of the Queen since she was six and waited for hours to say goodbye.
“If I had had to wait until tomorrow morning or Friday, so be it,” she said, adding that she came prepared with a change of clothes, food and an umbrella.
“I’m still shocked that our Queen has sadly passed on,” she added.
“As I went closer to where Her Majesty was lying there, I did curtsy, I said thank you in my mind. I broke down in tears as I walked away from her.”
Valerie Prebble, 68, and her partner Neil Emberley, 67, from near Maidstone, Kent, said the queue was sociable and they met several people including Moya O’Shea, from Westminster.
Mr Emberley, dressed in his Scout uniform, said it was “very emotional for someone that we’ve known all our lives and also she’s a patron of the Scouts, so I had to come and pay my respects”.
The trio all said they cried, but Ms O’Shea added: “There’s also not just tears.
“I mean there’s also a loss, of course, for a nation and a loss for a family in mourning, but it’s also just such a significant part of history, and that makes you very emotional as well.
“We will never see anything like this again in our lifetimes, and certainly not with the person who served as a sovereign for so long and did it so well.”
Joseph Arujo, 18, from Los Angeles, said he paid his respects to the Queen at Westminster Hall after travelling from the US to witness “this moment in history”.
He told PA he queued for six hours and made friends in the line, but once he got into the hall it was “a whole other experience”.
“It was very – I would say – tranquil was the best word, it was a lot of silence and everyone almost mourning with the royal family, taking it in what was happening and realising the Queen was right in front of you.
“Everyone almost did a little bow in front of the casket.”
On whether he grew tearful, he said: “A lot of people around me did, I felt the emotions internal but, yes, it was definitely an experience being here.”
Roger Bennett, 70, from Crewe, Cheshire, was among those who entered Westminster Hall to be treated to the spectacle of the regular Changing of the Guard.
Mr Bennett described the journey through the hall, saying: “You get to go up some steps to what is in effect a balcony and watch the guards change because they change every 20 minutes.
“It was beautifully laid out inside, there were a number of ushers in uniform to make sure everyone was respectful.
“I have a great affection for Queen Elizabeth, who has been on the throne for as long as I have been alive.
“I was very moved, it was a very solemn occasion, everyone was very quiet and silent.”