American Airlines Flight 11 struck the north tower at the World Trade Center complex at 8.46am local time in New York on 11 September 2001.
Five hijackers had taken control of the plane and forced themselves into the cockpit after the flight departed Boston’s Logan Airport.
At 9.03am, a United Airlines 767, which was hijacked after leaving Washington Dulles Airport, crashed into the south tower at the World Trade Center.
US President George W Bush has his early morning school reading event interupted by his Chief of Staff Andrew Card, who informs him that a second plane has crashed into the World Trade Center in New York.
New York City firefighters at the World Trade Center after the towers are struck by hijacked commercial aircraft.
The view from Brooklyn as dark smoke rises above Manhattan from both towers at the World Trade Center on 11 September 2001.
Officials examine the crater at the crash site of United Airlines Flight 93 in Shanksville, Pennsylvania. The plane had been hijacked, with principal instigators of the attacks claiming in the aftermath that the intended target was the US Capitol Building. Passengers on the plane, who had learned of the other attacks, fought back against hijackers, ultimately forcing the plane to crash into a field in Pennsylvania. All those on board were killed.
At 9.37am, American Airlines Flight 77 struck the west wall of the Pentagon in Arlington County, Virginia, across the Potomac River from Washington DC.
People in Manhattan watch the World Trade Center burning after the two hijacked planes crashed into the twin towers.
The south tower, the second of the two towers to be hit, collapses at 9.58am, around 56 minutes after impact.
Marcy Borders pictured covered in dust as she takes refuge in an office building after one of the World Trade Center towers collapsed.
The north tower, the first tower to be struck by a hijacked plane, is the second tower to collapse.
It collapsed at 10.28am, 1 hour and 42 minutes after the impact of the commercial aircraft.
People run away from smoke and debris as the second tower of World Trade Center collapses in Manhattan.
Policemen and firemen run away from the huge dust cloud caused as the World Trade Center’s Tower One collapses.
A salesman in an electronics store in Mexico City watches coverage of the attacks on the World Trade Center in New York.
Crowds flee Manhattan over the Manhattan Bridge on the morning of 11 September.
US President George W Bush sits at his desk in the Oval Office after addressing the nation about the attacks on New York and Washington DC.
Rubble at the World Trade Center complex in the aftermath of the attacks.
New York Governor George Pataki, New York City Mayor Rudolph Giuliani and US Senator Hillary Rodham Clinton tour the site of the World Trade Center attack on 12 September.
A wall of photos for missing loved ones at Union Square Park in Manhattan following the attacks.
US senators and represenatives gather on the east steps of the Capitol Building in Washington DC and sing ‘God Bless America’.
A person holds The Guardian newspaper in Rome in the days after the 11 September attacks.
Vigils for peace and remembrance are held in the days after the attacks. The US Congress passed the Authorization for Use of Military Force of 2001 just three days after the attacks, granting the president authority to use all necessary and appropriate force against those responsible. Only one representative votes against the resolution.