The full Instagram caption:

NASA Remembers September 11, 2001: Visible from space, a smoke plume rises from the Manhattan area after two planes crashed into the towers of the World Trade Center. This photo was taken of metropolitan New York City (and other parts of New York as well as New Jersey) the morning of September 11, 2001. “Our prayers and thoughts go out to all the people there, and everywhere else,” said Station Commander Frank.

In 2012, The Atlantic reported the story of astronaut Frank Culbertson, the only American not on Earth on September 11th, 2001:

After the attacks brought down the Twin Towers, Culbertson wrote a an emotional letter from the International Space Station:

It’s horrible to see smoke pouring from wounds in your own country from such a fantastic vantage point. The dichotomy of being on a spacecraft dedicated to improving life on the earth and watching life being destroyed by such willful, terrible acts is jolting to the psyche, no matter who you are. And the knowledge that everything will be different than when we launched by the time we land is a little disconcerting. I have confidence in our country and in our leadership that we will do everything possible to better defend her and our families, and to bring justice for what has been done. I have confidence that the good people at NASA will do everything necessary to continue our mission safely and return us safely at the right time. And I miss all of you very much. I can’t be there with you in person, and we have a long way to go to complete our mission, but be certain that my heart is with you, and know you are in my prayers.

Read the whole thing.