Hijacked United Airlines Flight 175 from Boston crashes into the South Tower of the World Trade Centre at 9.03 am in New York City on September 11, 2001. AFP
A man calling out asking if anyone alive trapped amid the rubble needs help after the collapse of the first tower on 9/11. AFP
Marcy Borders, known as the 9/11 Dust Lady, seeks refuge in an office building after the twin towers collapsed. AFP
Former US president George W Bush with firefighter Bob Beckwith and other rescue workers on September 14, 2001, at the site of the destroyed World Trade Centre. AFP
Businessman Edward Fine, who survived the attack after walking down 87 floors of the WTC North Tower, is covered in ash as he walks through the debris. AFP
Smoke billows from the twin towers of the World Trade Centre after the hijacked planes crashed into them. AFP
The collapse of the twin towers led to toxic dust, asbestos and glass fibres in the air, while underground fires smouldered at Ground Zero until December 2001. Reuters
Debris covers streets including Park Row, which is nearly half a kilometre away from Ground Zero, after the towers collapsed. AFP
Workmen begin dismantling the destroyed remains of the World Trade Centre on September 17, 2001. EPA