Can you remember a time when you looked into the sky and saw nothing, heard nothing. Not a high-altitude roar, no glint from the reflection of the sun, no flashing lights, or vapor trails.

Can you remember of a time? In my lifetime it has only happened once.

Once planes started to fall from the sky on 9/11/2001, the unprecedented decision was made to land all other flights across the nation. The skies would remain silent for the next seven days.