A sentence found scribbled on a dollar bill (back when Canada had one-dollar bills). Never found out whether it was a quotation or just somebody's spontaneous thought. Somebody here might know.
When you think about it, it nicely sums up our current state of civilization. Progress has made true silence nearly impossible. Within city limits, it's only in a power failure that can you get back in touch with the world's natural state, and even then it's only until the next car drives by.