On the morning of 11 September 2001, 19 Al Qaeda terrorists hijacked four commercial passenger planes in the United States.
Two planes were flown into the Twin Towers of the World Trade Center in New York City, causing both towers to collapse.
The fourth plane crashed in rural Pennsylvania after the crew and passengers attacked the terrorists on board, preventing the other target thought to be The White House
A section of twisted and rusted steelwork was lifted from the ruins of the World Trade Center and is now on display at IWM London.
The attacks claimed nearly 3,000 lives and impacted many more globally. On 20 September, US President George W Bush declared a 'War on Terror' .