Caves hide an enormous number of secrets—ones even scientists cannot fully unravel. For instance, how can you explain, from a scientific perspective, that in every single religion and in mystical cultures there are caves and grottoes that are sacred? And even today pilgrims from all over the world come here to worship their gods, make secret wishes, and ask for help in the most hopeless situations. Do the wishes come true? Probably—otherwise the path to them would have long since dried up, perhaps the only truly right one on our Earth. Caves and underground passages have been, and remain, an important part of human life. This audio book tells you about the most interesting of them.