On 11 September 2001, members of a terrorist organization hijacked four planes and commenced a coordinated attack on the United States of America.

American Airlines Flight 11 crashed into the North Tower of the World Trade Centre, between floors 93 and 99, at approximately 8:46am. All 81 passengers on board, including five hijackers, died instantly. Hundreds of people in the tower were also killed and many more remained trapped as stairwells became impassable.

At approximately 9:03am, United Airlines Flight 175 crashed into the South Tower of the World Trade Centre, between floors 77 and 85. The 65 passengers, including five hijackers, were killed, as well as many people inside the tower.

American Airlines Flight 77 hit the Pentagon at approximately 9:37am, killing all 64 passengers on board, including five hijackers, and the 125 workers inside the building.

The fourth flight, United Airlines Flight 93, was hijacked by four people but failed to reach its target of the Capitol or the White House in Washington DC. This was due to the actions of the 44 passengers on board who planned a revolt against the hijackers and attempted to retake the plane. The plane crashed into a field 129 kilometres south-east of Pittsburgh, Pennsylvania, approximately 20 minutes by air from the intended destination.

At approximately 9:59am the South Tower of the World Trade Centre collapsed, followed by the North Tower at 10:28am.

In total, the attacks caused the deaths of 2,819 people from 115 different nations. Only 289 bodies were found. There were 11 Australians amongst the dead. The attack and crash sites represented the largest crime scenes in the history of the Federal Bureau of Investigation.

The cleanup cost approximately $600 million.

Due to the loss of Australian lives, this event has been included in this dataset.