Cave exploration, or pot-holing, as it has come to be known, is a relatively new sport.Perhaps it is the desire for solitude or the chance of making an unexpected discovery that lures people down to the depths of the earth.It is impossible to give a satisfactory explanation for a pot-holer's motives.For him, caves have the same peculiar fascination which high mountains have for the climber.They arouse instincts which can only be dimly understood.Exploring really deep caves is not a task for the Sunday afternoon rambler.Such undertakings require the precise planning and foresight of military operations.It can take as long as eight days to rig up rope ladders and to establish supply bases before a descent can be made into a very deep cave.Precautions of this sort are necessary,for it is impossible to foretell the exact nature of the difficulties which will confront the pot-holer.The deepest known cave in the world is the Gouffre Berger near Grenoble.It extends to a depth of 3,723 feet.This immense chasm has been formed by an underground stream which has tunnelled a course through a flaw in the rocks.The entrance to the cave is on a plateau in the Dauphine Alps.
