An excellent post that brought back a flood of memories. From about 1969 to 1971 a group of us amateur cavers used to explore a cave very near the "Cradle of Humankind" we called it bat cave. I remember it had a circular hole in the ceiling at the bottom of which were bones of animals that had fallen in. I wrote post about it when I first started with steemit. Such a long time ago but the memories are still fresh.