Harry Clarke was driving a bin lorry through Glasgow city centre on 22 December 2014 when he passed out.
At about 14:30 the vehicle mounted the pavement and started striking Christmas shoppers on Queen Street.
Six people died in the crash - Erin McQuade, 18, and her grandparents Jack Sweeney, 68, and Lorraine Sweeney, 69, from Dumbarton; Stephenie Tait, 29, and Jacqueline Morton, 51, both from Glasgow; and Gillian Ewing, 52, from Edinburgh.
Ten years on eyewitnesses said the horror of the day remains seared in their minds.
Catriona Stewart was meeting a friend in a coffee shop when she saw the bin lorry speed past.
Ms Stewart, a journalist with first aid training, went out to see what happened when she heard screaming.
She said: "There were cars fanning out, there was people lying in the street, people screaming. It was a horrific scene.
"The chaos was quite spread out along Queen Street."
Just 19 seconds passed between the driver passing out and the vehicle coming to to a halt against the Millennium Hotel in George Square, leaving six people dead and 17 others injured.
Ms Stewart helped give first aid to an injured teenager lying on the ground.
And she said the sights and sounds of that day have never left her.
Ms Stewart added: "When I cycle to work I cycle along Queen Street and I find that very difficult, because the memories are so vivid.
"There are things I saw that day that I've never talked about and probably never will, because they are very personal to the other people involved, but they are very fresh in my head.
"It's astonishing to think it was 10 years because it feels like it was just last week."
Right Reverend Dr Gregor Duncan, the Scottish Episcopal Bishop of Glasgow and Galloway, was also on at the scene in the aftermath of the crash.
Now retired, he told the Press Association he will this weekend pray for the six victims, as well as the driver.
It later emerged Mr Clarke had previously passed out while behind the wheel of a stationary bus but did not tell his employers.
Right Rev Duncan recalled: "That afternoon I went out, and when I went back the road was closed off with lots of people around.
"I saw human remains on the road, some covered, some not.
"I realised something terrible had happened and went back to my office and put my clerical dress on."
The enormity of the tragedy soon dawned on the Bishop.
He said: "Someone said to me out of the crowd 'Five souls, Father' - by which she meant five people had been killed, at that stage, I didn't know how.
"She might have been asking me to pray for them."
Right Rev Duncan said Glasgow felt "stricken" in the aftermath of the crash, which came just a year after 10 people were killed when a police helicopter crashed into the Clutha pub, less than a mile away.
He added: "I think Glasgow felt afflicted. The time of year made it even worse.
"Some tragedies happen out of thin air, but others happen because of human error or human folly."
The city's Royal Exchange Square was piled high with floral tributes following the crash, and a candle-lit vigil was held in George Square.
A fatal accident inquiry held in 2015 found Mr Clarke "repeatedly lied" about his history of blackouts in order to gain and retain jobs with previous employer First Bus and with Glasgow City Council.
Adam Russell's mother Jacqueline Morton was among those killed in the disaster.
In 2015 he told BBC Scotland documentary, Lies, Laws and the Bin Lorry Tragedy: "I just keep on thinking that one day I'm going to take my two girls up to see their Granny Jackie at the grave and they're going to turn round and go 'What did happen to Granny, Daddy?'
"I'm just going to say 'Granny lost her life because a man lied.'"
In 2016 the then-Lord Advocate Frank Mulholland KC decided not to prosecute Mr Clarke, and said it was "the right decision" due to there being "insufficient evidence in law" for the case to go ahead.
Three years later, Mr Clarke told a Sunday newspaper the tragedy had been "an accident" and added: "There's not a day goes by I don't think about it."
In 2021, Glasgow City Council failed with legal action against First Bus regarding job references provided for Mr Clarke.