The spy agency released 71 declassified presidential briefings, with one showing it had thought Al Qaeda's plans were 'widely known' by extremists.

Paul Berriff says his life expectancy has been cut short because of being buried under rubble.

The BBC asks people in Washington what they were doing on that day and how 11 September 2001 changed the country.

Twenty-five years on, the attacks have come to define a generation of foreign, security and intelligence policy, the BBC's security correspondent writes.