1,463 stairs: Survivor recounts escape from World Trade Center led by guide dog

Others, though, were able to escape the towers before they collapsed.

Michael Hingson was in the first tower when it was hit. He had to make it down 78 floors inside a crowded stairwell.

And he did it with his guide dog.

When the first plane hit the tower, Hingson and hundreds of others crowded into stairwells trying to reach safety.

"We were not told as we were going down the stairs what was going on," Hingson said. "We smelled jet fumes on the stairs."

Hingson, who has been blind since birth, couldn't see a thing. His guide dog Roselle could, though.

"We worked as a team to get out," Hingson said of his dog. "She would stop at the top of every flight of stairs, and I could tell her to go forward.

A new guide dog is by his side now: Roselle died in 2011, but Hingson still travels around the country telling their story.

"Sometimes being a hero is just doing your job, which is what the dogs do," Hingson said.

As Hingson and Roselle descended 1,463 stairs, he never once thought he wouldn't make it.

"I immediately got this inner sense of conviction and peace that my guide dog and I would be OK," Hingson said.

So now, with his dog Africa, Hingson travels the country talking to people about some of the lessons learned, such as teamwork and acceptance.

"Blindness isn't the handicap," Hingson said. "Our attitude is the real handicap."

Hingson says he's moved on, but like most of us, still struggles with one thing.

"For me, I'm still just as awed that it happened," Hingson said. "How could anyone think of doing this kind of thing to us? How can people value life so little they're willing to fly an airplane into a building?"