#NeverForget: Nasa remembers 9/11 in poignant space photos
Monday marks the 16th anniversary of the terrorist attack that killed nearly 3,000 people when four hijacked planes hit the World Trade Centre towers and the Pentagon, and crashed in a Pennsylvania field.
Nasa astronaut Frank Culbertson was aboard the International Space Station (ISS) at the time of the attacks and the only American on the crew.
On hearing the news on September 11, 2001, he began documenting the event in photographs as the ISS was flying over New York City and captured incredible images within minutes following the event.
From his unique vantage point in space, he recorded the city changing beneath him, 250 miles above Manhattan.
Even from that distance, a massive debris cloud was visible emanating from the site of the trade centres.
The US space agency also shared satellite images of the tragic event.
“The smoke seemed to have an odd bloom to it at the base of the column that was streaming south of the city,” Culbertson recalled in the aftermath of the terrorist attack.
“After reading one of the news articles we just received, I believe we were looking at NY around the time of, or shortly after, the collapse of the second tower. How horrible.”
The astronaut had been on the ISS for almost month when he took the photo.
Culbertson spent another three months on the ISS before returning to Earth on December 17. It was his final trip into space.