Photographer: Sean Adair
On the morning of September 11, 2001, al-Qaeda terrorists hijacked four aircraft over the skies of America and flew them into the Twin Towers in New York City, the Pentagon in Virginia and crashed a fourth in rural Pennsylvania after passengers on board revolted.
The attacks shocked the world. It remains the deadliest terrorist incident in history - almost 3,000 people died - and caused billions in damage, as well as the destruction of the entire World Trade Center after the Twin Towers collapsed.
In response the US launched the War on Terror, invading Afghanistan and hunting down Osama bin Laden, who was eventually found and killed in Pakistan in 2011.
- 2001-09-11 Two passenger planes hijacked by terrorists crash into New York's World Trade Towers causing the collapse of both and deaths of 2,752 people
- 2001-09-14 Historic National Prayer Service held at Washington National Cathedral for victims of the September 11 attacks. A similar service is held in Canada on Parliament Hill, the largest vigil ever held in the nation's capital.
- 2001-10-02 NATO backs US military strikes, following 9/11
- 2001-12-24 "Time Magazine" names New York Mayor Rudy Giuliani 'Person of the Year', for leadership after 9/11 attacks
- 2002-11-14 The United States House of Representatives votes not to create an independent commission to investigate the September 11 attacks
- 2004-04-08 U.S. National Security Advisor Condoleezza Rice testifies before the 9/11 Commission
- 2004-04-29 Dick Cheney and George W. Bush testify before the 9/11 Commission in a closed, unrecorded hearing in the Oval Office
- 2014-11-03 New York's 104-storey One World Trade Center officially opens 13 years after the September 11 attacks