WARNING: Distressing content
On this day 18 years ago, unimaginable horror struck America when four commercial flights were hijacked by terrorists and crashed into sites including New York City's Twin Towers.
The morning of Tuesday, September 11 was fine and sunny, with New Yorkers navigating the manic rush-hour commute to
work or school under a cloudless blue sky.
But at 8.46am the unthinkable happened: American Airlines Flight 11, bound for Los Angeles, was hijacked by members of Al-Qaeda at Boston airport and flown into the North Tower of the World Trade Centre.
People stared up in confusion and disbelief at the smoking building, wondering if perhaps it was an accident, until 17 minutes later a second plane, United Airlines Flight 175, hit the South Tower at 9.03am.
