Heartbreaking video reveals what the only American in space on 9/11 saw as terror attack took place

The only American to have no been on Earth at the time of 9/11 recalled what it was like seeing the aftermath unfold from space.

Astronaut Frank Culbertson was at the International Space Station (ISS) on the fateful day that was 9/11, with today marking 23 years on from the devastating event.

Many people across the globe will have watched the news of the terrorist attack on their TVs, heard it on the radio, or read it in the paper the next day - but Culbertson had a birds-eye view from space.

Frank Culbertson was the only American in space at the time of 9/11 (NASA/YouTube)

He was the only American astronaut onboard the ISS at the time, which was in low orbit on the day in question - meaning that they had a clear view of Earth.

Years on from the sad day that claimed the lives of thousands of people, Culbertson recalled what he saw from space.

Speaking on the Astronauts: Houston We Have a Problem documentary in 2014, he said as per VT: "The weather was perfectly clear that day. I could easily see New York City - a big black column of smoke coming out of the city, and as I zoomed in with the video camera, I could see this big grey blob enveloping southern Manhattan."

Plumes of smoke seen in Manhattan in satellite images taken from the ISS (NASA/YouTube)

The 'grey blob' he and his fellow astronauts could see was, in fact, the second of the Twin Towers coming crumbling down.

Elsewhere in a video shared on NASA's YouTube channel, Culbertson also remembered seeing 'a big cloud of debris covering Manhattan'.

Recalling receiving the news from Earth about what had happened, the astronaut went on: "That's when it really became painful, because it was like seeing a wound in the side of your country."

While Culbertson found about about the 9/11 attacks in space, president at the time George W. Bush was in a classroom full of kids when he received the devastating news.

The moment he was told about it was caught on camera.

Reportedly Bush already been informed a plane had hit the World Trade Center before arriving at Emma E. Booker Elementary School that morning, however he under the impression that it was a 'pilot error'.

It was only while was sat in front of a group of young students that he learnt the true extent of the crash.

In the video, the White House's Chief of Staff at the time Andrew Card is seen whispering to the president: "A second plane hit the second tower. America is under attack."

But rather than rushing to his feet, Bush kept his cool in front of the children and continued his visit.

He later spoke of the event in the BBC documentary, 9/11: Inside the President's War Room, saying: "I could see the horror etched on their face of the news people who just got the same news. And so I watched for the appropriate moment to leave the classroom.

"I didn't want to do anything dramatic, I didn't want to lurch out of the chair and scare the classroom full of children.