In the world of dreams the rules of reality do not necessarily apply. Each dream is unique and it's a direct link to the soul and spirit. Psychology provides its own theories on what dreams mean, but so did tradition and the study of dreams for thousands of years before any relevant science had developed.
Dream Meanings - Cave
To dream of a bright, clean cave means you will have joy and happiness in life, but if it’s dark you will have difficulties. Watch out if the cave has snakes as this mean you have enemies.