Believe it, folks. This large-scale rock structure is actually a playable synthesizer.
In a video that popped up on Reddit earlier today, footage displays a man moving a stone across the surface of an ancient rock wall, creating new sounds as he passes different sections of the wall. The wall is cut into symmetrical squares, visually looking quite similar to a drum machine, with each section of the wall playing new sounds.
The video, however, seems to be a re-upload, and the YouTuber has not credited where they have sourced the video, so if anyone has any context for the video, please comment.
For now, check out the oldest synth getting played below.