Is There A More Inspiring Twilight Zone Than "The Changing of the Guard"?

If you ever saw it you will remember it.  Teacher at an elite boys school considers suicide after being forced into retirement because he feels like he made no mark on the world. Then the ghosts of former students appear.  Each has a story of courage from what he taught them: Congressional Medal of Honor posthumously awarded for Iwo Jima; doctor who died of radiation poisoning research medical use of X-rays; etc.

For those of us who teach we have at least a few reminders of marks we have left on lives: a young man whose parents worried that he would not go anywhere because he was not interested.   My American History class inspired him.  The last I heard I was writing a recommendation for some Army training program. 

I have no idea how many other marks I have made but like the professor you know that there are more than you immediately realize.