A series of events will take place on Thursday in the United States to mark the 24th anniversary of the 9/11 attacks.
On Tuesday 11 September 2001, suicide attackers seized US passenger jets and crashed them into two New York skyscrapers, killing thousands of people.
The event had profound consequences across the globe.
Which buildings were targeted?
Four planes flying over the eastern US were seized simultaneously by small teams of hijackers.
They were then used as giant, guided missiles to crash into landmark buildings in New York and Washington.
Two planes hit the Twin Towers of the World Trade Center in New York, with the second strike 17 minutes after the first.
The buildings were set on fire, trapping people on the upper floors, and enveloping the city in smoke. In less than two hours, both 110-storey towers collapsed in massive clouds of dust.
A 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 after passengers fought back. It is thought the hijackers had meant to attack Washington’s Capitol Building.
How many people died in the 9/11 attacks?
