Source: https://www.instagram.com/p/DeosvvZo5H0/

Lithophones might be some of the oldest musical instruments. There are traces from the Upper Palaeolithic (Solutrean period, approx. 22,000–17,000 years ago*) that suggest the musical use of rocks. The video posted here includes a boulder with a remarkable bell-like sound.

Here is footage of another example from Sudan:

This is a snippet from “Lost Kingdoms of Africa: Nubia”

*Referring to the Nerja cave:
“The cave of Nerja contains at least 19 paintings so far reported, and has excellent acoustics, such that it is now sometimes used as a venue for concerts and dance in the summer months. It also contains a feature known as “the organ”, which consists of an area in an alcove where the calcareous deposits have formed into a fluted, concertina-like feature. […] the style of the ibex and hind illustrated suggest a Solutrean (c.22-17 Kya) age for the illustrations […]”
https://www.darwin.cam.ac.uk/wp-content/uploads/2024/11/dcrr002.pdf -> Page 70 (page 82 in the PDF)

At this point I also can’t help but remember the Great Stalacpipe Organ:
https://en.wikipedia.org/wiki/Great_Stalacpipe_Organ