New NASA video shows an astronaut's painful view of the 9/11 World Trade Center attacks from space

The terrorist attacks on the World Trade Center on Sept. 11, 2001 were not only viewed from around the world -- a NASA astronaut noticed the traumatic event from space.

Astronaut Frank Culbertson was the only American not on Earth on that fateful day, according to NASA. Sitting in the International Space Station, Culbertson had an incredible view of the attacks.

In a new video released by NASA for the 10th anniversary of 9/11, Culbertson said he didn't understand what was happening when he first spotted the smoke.

"I knew it was really bad because there was a big cloud of debris covering Manhattan," Culbertson said. "That's when it really became painful because it was like seeing a wound in the side of your country, of your family, your friends."