'Caves' in the Bible

(Of whom the world was not worthy:) they wandered in deserts, and in mountains, and in dens and caves of the earth.

For God did not spare angels when they had sinned, but hurling them down to Tartarus consigned them to caves of darkness, keeping them in readiness for judgement.

Then the kings of the earth, the nobles, the military commanders, the rich, the powerful, and every slave and free person hid in the caves and among the rocks of the mountains.