The sound of silence
Silence is the canvas that music is painted on. The purpose of silence in music is much greater than to serve as mere canvas. Classical composers have used silence very effectively in their compositions for hundreds of years. Most of them had exceptional control over silence and that reflects in their work.French composer Claude Debussy (1862-1918) said: "Music is the silence between the notes." This is easy to understand when one understands the different context of silence. A silence can be comfortable, uncomfortable, dishonest, edgy, uneasy, all depending on its context. The most profound usage of silence in music, probably originates from human language and the silence used between words.
Marching to the silent war drum
Military marching is historically connected to the marching drum. A marching drum without silence looses much of its tension. The silence between drum rolls is the key to building up tension in a march, a constant drum roll on the other hand is predictable and therefore lacks tension. A very good example of this is the main theme from the film Where Eagles Dare.
The theme starts off with a snare drum rolls with a healthy amount of silence between them. This creates an initial tension that is used throughout the theme. Then the music starts the impression of silence has a firm foothold in the mind of the listener, imaginary silence is created by repeating it at the start and throughout the theme. Towards the end the silence becomes a dominant factor when the whole orchestra mirrors the initial silence.