Down in the Valley

"Down in the Valley" was a traditional American song.

As a child, Deanna Troi would often enjoy hearing her father, Ian Andrew Troi, sing to her. The song she requested most was "Down in the Valley".

In 2370, Troi listened to an illusion of her father sing an excerpt from the song while telepathically exploring her mother's brain. 

Lyrics
Down in the valley, valley so low, Hang your head over, hear the wind blow 
 * – Excerpted from "Down in the Valley"