When I arrived at the West Side Highway a minute before, a huge column of smoke and dust was rising, obscuring the south tower. Someone standing in the median yelled that the whole tower had collapsed. Most of the other people responded skeptically.

How could a building that massive collapse?

The dust cloud had settled enough for us to see the incomprehensible truth. The south tower wasn't there any more.

A fire engine raced by.

People covered in soot with shocked looks on their faces streamed by heading north, as far away from downtown as they can get.

And then the north tower collapsed. It seemed to take a long time to fall, and because you couldn't hear any sounds, it felt like you were watching it in slow motion.

They were both completely gone now.

All those people. The ones I had seen on TV as I was leaving the apartment. The ones waving for help from the windows. And the rescue workers rushing in to help.

How could this happen?