Putting these timestamps here for a reference. Do we need these this week?

Two planes struck the Twin Towers of the World Trade Center in New York.

The first hit the North Tower at 08:46 Eastern Time (12:46 GMT). The second crashed into the South Tower at 09:03.

The buildings were set on fire, trapping people on the upper floors, and wreathing the city in smoke. In less than two hours, both 110-storey towers collapsed in massive clouds of dust.

At 09:37 the third plane destroyed the western face of the Pentagon - the giant headquarters of the US military just outside the nation's capital, Washington DC.

The fourth plane crashed in a field in Pennsylvania at 10:03 after passengers fought back. It is thought the hijackers had meant to attack the Capitol Building in Washington DC.