Suddenly the ground disappeared from beneath his feet. He fell down a vertical shaft, his head hitting a sharp rock. Hhe lost consciousness. On opening his eyes, he found himself with the Professor and the guide, and, looking around him, he saw an ocean stretching as faras the eye could see, a giant forest of mushrooms, a line of huge cliffs, and strange clouds hung overhead, as he lay on a deeply indented shore of golden sand strewn with shells. For a moment, he thought he was back on the surface of the earth, but soon realised that they had reached a world within a world.