The great pillars which adorn this noble hall are calcareous deposits, formed by the everlasting droppings from the percolated roof above. We picked our way further downwards over a wooden staircase, with the natural roof rising over us into arch after arch of great beauty, but irregular form. The guide, accompanied by the boy moving on in front with blazing torches, looked like some demon with his attendant imp luring us spell-bound into some vast and fatal labyrinth. One great hall in which we found ourselves was noble and grand in appearance. In the middle of the gloom loomed masses of fretted white stalactite, rising upward in spiral forms, while some tall, slender objects appeared like the graceful stems of palm-trees capped with feathery plumage. These were formed by the pillars, as they joined the roof, being pushed backwards and spread out like boughs of drooping foliage. In another chamber called the Hall of the Virgin, a marvellous effect was produced. In the middle of the spacious concave we dimly perceived some lofty object of a grey and misty hue. "Momento," said the guide, "don't move;" and in another instant a blue light was kindled. No words can describe the effect that was instantaneously produced. The walls shone like crystal of dazzling brilliancy. The roof was like a firmament ablaze with a million stars. The numerous columns that supported it were adorned with a profusion of filigree work which had some resemblance to Gothic tracery. A lofty marble-like pedestal, apparently supporting a graceful female figure which, amidst many folds of gauzy drapery of the most brilliant whiteness was caressing a sleeping infant, composed a group at once beautiful, majestic, and serene. In the Hall of the Organ there is a great number of airy white pillarets collected in a mass, which in the gloom natural to these subterranean halls have some resemblance to the pipes of an organ. Wandering about in passages that appeared almost like aisles in nature's temple, we anticipated every moment a burst of mysterious melody in harmony with the wonderful character of a place so rarely seen by human eye. The name of the Hall of the Curtain is sufficiently suggestive of what is to be seen in the chamber so designated. A wall of dazzling white stone is of such airy texture that it seems in the fitful glare of the torches to be driven backwards and forwards by the wind. So, in the Hall of the Banners, a flag appears to be drooping from its staff and occasionally waving in the breeze. We know it is only a delusion, but for the moment it is wonderfully like reality. As we followed our guide in these awful caverns by stairway and corridor, through hall and gallery, we could almost imagine that we were pacing the courts of some buried palace of some long-forgotten Titan race.