A woman died and four people were injured when a crane collapsed on to houses and a block of flats which were being built in London.
The 20m (65ft) crane crashed on to the development and two terrace houses in Compton Close, Bow, before 14:40 BST.
The woman was found on the first floor of one of the houses and died at the scene. Four others were injured, including two people taken to hospital for head injuries.
A police blockade remains in place.
The crane collapsed where a block of flats was being built in Watts Grove and crashed on to two adjacent houses.
A woman whose home was one of those damaged said she and her family were "so lucky to be alive".
"The way that everything fell - if my brother or sister had been in their rooms which is where it hit directly, I just cannot bear to think about it," she said.
The woman, who asked not to be identified, described the sound of the collapse as being "like an earthquake", adding that she had been left "traumatised" by what had happened.
Another witness described "feeling the ground shake" when the crane collapsed.
DJ Munro, who lives nearby, said he heard "the metal of the crane crushing against the scaffolding and then the wood crushing in the house".
A video posted on social media showed a terrace house with part of the roof collapsed.
Eyewitness Bridget Teirney said she believed the crane driver had escaped safely.
The crane that collapsed was being used by Swan Housing Association and NU living at the time.
A spokeswoman for Swan Housing Association and NU living said they were "deeply saddened by an incident that occurred at our Watts Grove development site this afternoon".
"Our staff are on site to provide support to the emergency response and the investigation."
Jerry Swain, national officer for union Unite, said there had to be "an urgent, full and complete investigation into the circumstances that led to this accident".
He added: "The preliminary findings of which must be released in weeks, rather than months or years, in order to ensure that similar accidents are avoided in the future."
London Ambulance Service tweeted to say it had "a number of crews and specialist resources" at the scene.
LFB assistant commissioner Graham Ellis said securing the house had been a "complex rescue operation".
Mr Ellis said: "Our Urban Search and Rescue crews undertook a complex rescue operation and used specialist equipment to search the properties."
London's Mayor Sadiq Khan said the collapse was "a tragedy" and his "heartfelt condolences go out to the family of the victim who died".
"We must ensure the lessons are learned so an accident like this never happens again," he added.