A sharp reply can sometimes teach more than a long lecture. One such story is told about Plato, the Greek philosopher whose ideas still shape how people think about knowledge, justice, character and society.

A great leader is often remembered through speeches, marches and political decisions. But sometimes, a small joke tells us just as much.

A moving train makes more than noise. To most passengers, the rhythm of wheels on rails is only background sound. To a trained engineer, that rhythm can become a warning.