Introduction to goose tubes: Thousands of milky white tubular stalactites grow densely on the roof of the cave, shaped like goose feather tubes, as ice-like as jade, crystal clear. What is even more wonderful and confusing to tourists is that the center of each tube is empty and the walls are as thin as paper. Sometimes karst water drips along the goose tube, and occasionally drips onto the body and face of tourists, giving it a chilling feeling. a feeling of. The goose tubes in Boyue Cave are of different lengths and scattered at random. Its large area and high density make it the second largest "world's largest".