Earth Harp

Earth Harp: It is a musical instrument where free floating strings anchored at long distances on building, or a canyon. It’s the world’s longest instrument. Ther anchor it on landscapes and architecture to play.

It’s so large that the audience is effectively inside the instrument.

William Close is the guy who invented this instrument.

https://www.bbc.com/news/av/entertainment-arts-51551542/earth-harp-the-man-behind-the-unique-instruments-epic-sound

http://www.earthharpsymphony.com/

https://www.youtube.com/watch?v=qrjcOpq_Nw0