18 years since 9/11: The horror of September 11 terror attacks in 10 photos

Warning: This article contains graphic content.

Eighteen years ago today, the world was changed forever when 19 terrorists hijacked four planes and successfully flew three of them into major US landmarks.

In the morning of September 11, 2001, American Airlines Flight 11 and United Airlines Flight 175 were flown into the North and South Towers of New York's World Trade Centre. 

Shortly after, American Airlines Flight 77 was flown into Virginia's Pentagon building, and United Airlines Flight 93 crashed near Shanksville, Pennsylvania. Less than half an hour after the fourth commercial flight crashed, both Twin Towers had collapsed.

In less than two hours, 2996 people were killed and more than 6000 injured.

September 11 remains just as significant and just as poignant as it did 18 years ago. To mark the 18th anniversary of the September 11 attacks, here are 10 photos the world should never forget.

9/11: A firefighter breaks down
A firefighter breaks down after the World Trade Center buildings collapsed. Photo credit: Getty/Mario Tama
9/11: Smoke trail, New York skyline
Smoke trail from the Twin Towers over the New York skyline. Photo credit: Reuters
9/11: Plane hits World Trade Centre
A plane hits the World Trade Centre, bursting into flames. Photo credit: Reuters
9/11: A man falls to his death
A man falls to his death from the World Trade Centre. Photo credit: Getty
9/11: People hanging out the windows of the World Trade Centre.
People hang out the windows of the World Trade Centre. Photo credit: Getty
9/11: The Pentagon on fire.
Firefighters work to put out the flames at the Pentagon in Virginia. Photo credit: Getty
9/11: A fatally injured man is rescued from the rubble by firefighters.
A fatally injured man is rescued from the rubble by firefighters. Photo credit: Reuters
9/11: World Trade Centre, top floors collapse.
The top floors collapse. Photo credit: Getty
9/11: The first hijacked plane hits, bursting into flame behind the American flag.
The explosion, captured behind the American flag. Photo credit: Reuters
9/11: Civilians watch on as the second Tower collapses.
Civilians watch on as the second Tower collapses. Photo credit: Reuters

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