shhhhhhhh!

To be fair, for this post I could just include white space and nothing else. However...

Composer John Cage's piece 4'33" is basically 4 minutes, 33 seconds of complete silence. But supporters of Cage would argue that the experience is different for each listener and the piece includes the sounds of the environment it is played in. Composed in 1952, it can be played by any combination of instruments. Cage explained his piece by saying: "[W]hatever we we are[,] what we mostly hear is noise."

When Mike Batt composed A One Minute Silence, Cage's estate sued him. While Batt payed an undisclosed 6-figure amount to the John Cage trust, he retorted: "Mine is a much better silent piece. I have been able to say in one minute what Cage could only say in four minutes and 33 seconds."

Here you can see 4'33" performed with a full orchestra. While there is a conductor, he only lifts his baton to give the downbeat at the start of each of the three movements, and occasionally turns pages. Here you can see it preformed by a solo piano who closes the piano lid and sits quietly with a stopwatch. If you are interested in Cage but don't have a large tolerance for silence, you might be interested to see an early work of his called Water Works. Here is is part of Cage's piano sonatinas. Be forewarned, they sound very different than what one is used to.

Source. Source.