Introduction to the sound of tides in the ancient cave: The cave is half submerged in the sea, about 30 meters deep, and about 10 meters deep from the cliff to the bottom of the cave. The coast here is zigzag, with rugged cliffs and layers of strange rocks. The bottom of the cave opens to the sea, and there are two gaps on the top, called skylights. The entrance of Chaoyin Cave faces the sea and looks like an open mouth. It is beaten by the waves day and night, and the tide rushes into the cave entrance with the force of a flying dragon and the sound of thunder.