A tsunami of smoke, dust and debris roars down the streets of New York City as the World Trade Centre towers collapse.
These dramatic images were taken by police photographers in helicopters and it is the first time they have been seen, having been released under a Freedom of Information request made by America's ABC News.
Burning buildings can be seen crumpling in on themselves as plumes of smoke rise up over the New York skyline that terrible September morning.
The images show how the police helicopter first began taking images from afar before moving in to reveal the devastation taking place underneath.
They also reveal the horror faced by those trapped in the burning buildings and then the walls of smoke and debris that enveloped the surrounding area as the towers came crashing down.
Released more than eight years after the deaths of 2,752 people on that day, they are powerful reminders of the attack that led to wars in Afghanistan and Iraq.
The legacy of the New York attack continues today with as British forces joining with Afghan soldiers and Nato to launch the biggest attack on the Taliban - accused of harbouring Al Qaeda who organised the 9/11 attack - since the initial 2001 offensive.
Meanwhile, in New York, work is continuing to build on the rubble of what became known as Ground Zero.
Structural steel for the 1,776ft tower, which will be known as 1 World Trade Centre, has already reached 200ft above street level.
Workers are now installing 16 steel nodes on the 20th-floor of the tower which will serve as joints between the steel framing for the building's podium and the steel for the rest of the tower. The 104-storey skyscraper is due to be completed in 2013 and will be one of the tallest buildings in the U.S.