The moment the CTV building collapsed has been recounted in the opening statements of the hearing into its failure.
The Royal Commission of Inquiry has begun its investigation into the building's collapse in last year's February earthquake, which claimed 115 lives.
The hearing is expected to take up to eight weeks.
The counsel assisting the Commission, Stephen Mills QC, says eyewitness accounts conclusively suggest the building's collapse was almost immediate.
"The effect on the CTV building was sudden and shocking. Most of the eye witnesses to the collapse who have been spoken to by council assisting have referred to the building collapsing in a matter of seconds. The concurrence of the eye witness views on this strongly suggests that the collapse was almost immediate."
Answers and closure are the two things CTV staff want out of the Royal Commission hearings into the collapse of their former building.
Dozens of people are set to give evidence. Among those giving evidence are people who witnessed the collapse, others who were pulled alive from the rubble and people who worked in the building and had concerns about its state.
The building's owner, Lionel Hunter, will be giving a statement to the commission though exactly when that will happen hasn't been set.
A Christchurch father who lost his only son in the building hopes the Royal Commission brings truth and justice.
Matthew Beaumont worked for CTV - he was one of 115 people who died.
His father, David, is confident the commission will find out why the building collapsed.
"I think in general it's a lot of minor things coming together that have added up to it, I think that's what my conclusion would be. We just want the truth out there, that's all we want."
Mr Beaumont says no blame needs to be laid over the collapse.
One of the focuses will be how the building was assessed after the September and Boxing Day quakes, before the fatal one on February 22.
CTV presenter Rob Cope Williams says that's something staff want answers on - especially given they raised concerns about the damage caused by those quakes.
"Why were we allowed to carry on working in there? Why was it not closed down, a long with a lot of other buildings in Christchurch?"
Mr Williams says there were numerous cracks in the building, staff were petrified and raised concerns with the station's management.
"And all they could do is accept their reassurances. It's going to be a very interesting six to eight weeks."
He says the hearing will force those connected to the CTV building to relive the pain around its tragic collapse.
And it's a big morning for around 70 school students who will open the commission's hearing this morning.
St Teresa School's kapa haka group and choir will be performing Mo Maria and the Irish Blessing at 10 this morning.
Principal Suzi de Gouveia says the students understand the importance of the occasion and hope to provide some comfort before the heartache.
"This is an honour for us to be invited to participate and if we can bring a little moment of peace to the people who are there to do the inquiry then that's our role."
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