Saturday is the 20th anniversary of the 9/11 attacks, which claimed the lives of thousands of people and changed the direction of US politics for two decades.
Twenty years ago, 19 hijackers took control of four passenger planes, flying three into buildings in New York and Washington before a fourth was brought down by its passengers in a field in Pennsylvania.
The attacks resulted in the deaths of 2,977 people: 2,753 at the World Trade Centre, 184 at the Pentagon and 40 in Shanksville, Pennsylvania.
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The run-up to this year’s anniversary has been tense in the US and abroad as bereaved family members voiced their opposition to Joe Biden’s participation in any memorial events unless he upheld his pledge to declassify government evidence that they believe shows a link between Saudi Arabian leaders and the attacks.
Meanwhile, the US deadly withdrawal from Afghanistan has led to questions about the rationale behind the invasion and occupation that followed 11 September. Here is how the day’s events unfolded:
7.59am
American Airlines Flight 11 takes off from Logan International Airport in Boston heading for Los Angeles, carrying 81 passengers and 11 crew members. Five hijackers are on board.
8.14am
United Airlines Flight 175 takes off from the same Boston airport also heading for Los Angeles. It is carrying 56 passengers and nine crew. Five hijackers are on the plane.
Meanwhile, Flight 11 is hijacked over central Massachusetts, first turning northwest, then south.
8.20am
American Airlines Flight 77, carrying 58 passengers and six crew, leaves Dulles International Airport near Washington for Los Angeles. Five hijackers are on board.
8.42am
United Airlines Flight 93, with 37 passengers and seven crew on board, departs Newark International Airport in New Jersey for San Francisco. Four hijackers are on the plane.
8.42–8.46am
Flight 175 is hijacked above New Jersey, around 60 miles northwest of New York City.
8.46am
Flight 11 crashes into the north face of the North Tower of the World Trade Centre, between floors 93 and 99.
8.50–8.54am
Flight 77 is hijacked above Ohio.
9.03am
Flight 175 crashes into the south face of the South Tower of the World Trade Centre, between floors 77 and 85. It becomes clear that the crashes are intentional.
9.10am
President George W. Bush is reading to children in a classroom in Florida when he is interrupted by his chief of staff, Andrew Card, whispering news of the attacks into his ear.
9.28am
Flight 93 is hijacked above Ohio.
9.37am
Flight 77 crashes into the western side of the Pentagon and starts a fire.
President Bush authorises F-16 fighter jets to shoot down any other aircraft that threatens targets in Washington.
9.45am
United States airspace is shut down, airports are closed and commercial flights are grounded. The White House and Capitol building are evacuated.
9.59am
The South Tower of the World Trade Centre collapses, 56 minutes after Flight 175 made impact. Many first responders are killed, along with hundreds more people who could not escape the falling tower.
10.03am
Flight 93 crashes in Pennsylvania, killing everybody on board. Passengers had learnt of the World Trade Center and Pentagon crashes and were resisting the hijackers, causing them to bring the plane down early. Moments before, a hijacker can be heard shouting: “Pull it down! Pull it down!”
The plane was 20 minutes away from its suspected target, either the White House or the Capitol Building in Washington.
10.28am
The North Tower of the World Trade Centre collapses, one hour and 42 minutes after the impact of Flight 11.
10.50am
Five storeys of the Pentagon collapse.
5.20pm
Seven World Trade Centre, a 47-storey building adjacent to the twin towers, collapses.
8.30pm
President Bush addresses the nation from the White House: “Today, our fellow citizens, our way of life, our very freedom came under attack in a series of deliberate and deadly terrorist acts.
“Terrorist attacks can shake the foundations of our biggest buildings, but they cannot touch the foundation of America. These acts shatter steel, but they cannot dent the steel of American resolve.
“The search is underway for those who are behind these evil acts… we will make no distinction between the terrorists who committed these acts and those who harbour them.”
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