Exactly 20 years ago, at around 8:46 a.m. on September 11, 2001 (Eastern time), American Airlines Flight 11 to Los Angeles was hijacked by al-Qaeda terrorists at Boston Airport. They diverted the plane to New York, and crashed it straight into the North Tower of the World Trade Center in the heart of the city.
New Yorkers were shocked and could not believe their eyes when they saw the tower on fire with black smoke billowing. At first, everyone thought it was just a plane crash, but then 17 minutes later, another plane, United Airlines Flight 175, suddenly crashed into the South Tower at 9:03 a.m. (Eastern US time).
Within just 1 hour, the 145 meter high twin towers collapsed into ashes, shocking the people of America and the world. Nearly 3,000 people, including hundreds of firefighters and police officers, could not survive the terrorist disaster considered the bloodiest, caused by an outside force in the United States.
It has been 20 years since the 9/11 terrorist attacks, but the pain and haunting memories of that horrific day are still deeply etched in the memories of witnesses, survivors and relatives of those who died. "It was a day of indelible images. Apocalyptic, surreal, violent, demonic. Painful to remember and unforgettable," an AP reporter described in an article marking the 20th anniversary of the terrorist attacks that shook the United States and shocked the world.
Let's take a look back at the images that Reuters news agency commented "shaped" the tragedy of September 11, 2001:

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The North Tower of the World Trade Center burns after being hit by an al-Qaeda-controlled plane on September 11, 2001. Photo: Reuters |
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New Yorkers were stunned as they watched smoke rise from the twin towers of the World Trade Center. Photo: Reuters |
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Many people inside the North Tower of the World Trade Center risked their lives to escape by climbing out of windows. Photo: Reuters |
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Close-up of the North Tower of the World Trade Center engulfed in smoke and fire after being hit by a plane. Photo: Reuters |
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The fire was so big that smoke from the World Trade Center could be seen for a great distance. Photo: Reuters |
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The subway exit near the World Trade Center is covered in smoke and dust after the horrific terrorist attack. Photo: Reuters |
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Firefighters try to rescue survivors from the World Trade Center. Photo: Reuters |
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The man was "white" from head to toe due to the smoke and dust from the disaster at the World Trade Center. Photo: Reuters |
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Within just 1 hour, the 145-meter-high twin towers were reduced to rubble. Photo: Reuters |
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Many vehicles parked near the World Trade Center were also burned to ashes. Photo: Reuters |
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The only thing left intact in the rubble was an American flag. Photo: Reuters |
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The 9/11 terrorist attacks claimed the lives of nearly 3,000 people, including hundreds of firefighters and police officers. Photo: Reuters |
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At the same time as the terrorist attack on the World Trade Center's twin towers, another plane hijacked by al-Qaeda crashed into the Pentagon, killing 29 people. Photo: Reuters |
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Meanwhile, the plane that was supposed to carry out the fourth terrorist attack was attacked by passengers and crashed into a field in Shanksville, Pennsylvania. All 44 people on board were killed. Photo: Reuters |