The sound of "Babel" by Cildo Meireles in the Tate Modern - the catalogue description reads: 

"Babel 2001 is a large-scale sculptural installation that takes the form of a circular tower made from hundreds of second-hand analogue radios that the artist has stacked in layers. 

The radios are tuned to a multitude of different stations and are adjusted to the minimum volume at which they are audible. Nevertheless, they compete with each other and create a cacophony of low, continuous sound, resulting in inaccessible information, voices or music."

Recorded by Cities and Memory.