Pachebel's Canon in D Minor --a well-known baroque classical piece ....from the 16th or 17th century. Pieces have been used for commercials.
I choose this because it has several personal layers of meaning:
My dead sister's favourite classical music piece.
It was a piece that 2 of my other sisters each played for their wedding march.
For me the building of crescendo in music is like life....sometimes life is sad, joyous, rises in exhaltation and falls to rise again.
And above alll.....for me, it is the sensation of it feels like to cycle or snowshoe slowly towards a mountain that rises and becomes more and more enormous and more, magnificent with the sun either rising or setting behind it.