A Study of Distribution of Cave in South Korea

There are some 1,000 natural caves in Korea. Most caves on the mainland are made of limestone, whereas most of the caves on Cheju Island are volcanic in origin. The caves on Cheju, in particular, are internally renowned for their huge size and scientific value. By contrast, the caves on the mainland are not as big, but their unique shapes and formations still attract the attention of international speleologists.(omitted)