"THE HILLS are alive with the sound of music" – so goes the opening line from the song performed by Maria, famously played by Julie Andrews, in the movie The Sound of Music.
When we think about music, we immediately associate it with what we can hear – whether it's the sweeping sound of an orchestral symphony, the catchy beat of a pop song or just singing in the shower.
However, is there any music composed that is completely silent?
Verdict:

TRUE
There are, in fact, several compositions where not a single note is played or heard.
The most famous is by American composer John Cage, simply titled 4'33'' (pronounced four minutes, thirty-three seconds – which is, as obvious, the length of the piece). It was written in three parts (or three movements, in musical terminology) and performers are instructed not to produce any sound for its entire duration.
First performed in 1952 at Maverick Concert Hall in New York, pianist David Tudor walked onto the stage, sat at the piano with stopwatch in hand, and then closed the keyboard lid, signalling the beginning of his performance. After 30 seconds, he opened the lid again to mark the end of the 1st movement. He repeated this twice, keeping the lid closed for one minute and 23 seconds, and then for another 40 seconds. Without striking a single key for four minutes and 33 seconds, Tudor then stood up and bowed.
While some may view 4'33'' as a joke, Cage was completely serious about his intent. The point of the composition is to show that true silence does not exist. By forcing the audience to just listen, they start to hear ambient sounds such as the shuffling of feet, a muted cough or even traffic sounds seeping into the venue.
In his collection of essays titled Silence, Cage wrote of his experience in an anechoic chamber. While it is supposed to be completely silent, he heard two distinct sounds of different pitches – one high and one low. He was told the high-pitched sound was his nervous system and the low was his blood circulating.
"Until I die, there will be sounds… and they will continue after my death. One need not fear about the future of music. Any sounds may occur in any combination and in any continuity," he wrote.
Another piece is by French writer Alphonse Allais in his 1897 work, Marche funèbre composée pour les funérailles d’un grand homme sourd (Funeral March for the Obsequies of a Deaf Man). He was not a musician per se, but more of a humorist and the piece consists of 24 blank bars of "music".
And in 1919 Dadaist artist Erwin Schulhoff (1894-1942) published his work 5 Pittoresken, Op. 31. Written in five movements on a single page it is filled with impossible time signatures, with each measure filled out with rests.
The best way to appreciate Cage's 4'33'' is to experience it for yourself. Here are two masterful performances of the work.
Sources:
1) From No Such Thing as Silence: John Cage's 4'33"
https://newmusicusa.org/nmbx/from-no-such-thing-as-silence-john-cages-433
2) There Will Never Be Silence: Scoring John Cage's 4′33″
https://www.moma.org/calendar/exhibitions/1386
3) The Sound Alternative: Alphonse Allais, Erwin Schulhoff and John Cage
https://interlude.hk/the-sound-alternative-alphonse-allais-erwin-schulhoff-and-john-cage/
4) The story of 4′33″
https://www.npr.org/2000/05/08/1073885/4-33
5) 4’33”: John Cage’s revolutionary “silent” musical piece
https://www.20k.org/episodes/433
