So a few days ago I was walking around in cemetery and passed by an old abandoned chapel (which seems to have had weird things going on around there) and saw this; a big rock with a perfectly round shaped hole in the middle of it and in the hole there was a perfectly ball-shaped rock. It looked like it was done by something but at the same time didn't look like a human did that. It seemed like something related with a ritual or something, if I'm not wrong. Anyone know what this may be? I'm just curious. And sorry if I'm just being stupidly wrong here.
Pics are here:
Thanks!