For those who are looking for an opportunity to go caving, various underground caves in Yishui county, East China's Shandong province, are ideal places where adventurers are treated to a majestic display of nature's hidden works of art.

About four hours' drive from the provincial capital of Jinan, Yishui is home to hundreds of natural karst caves, which have a length ranging from several hundred meters to nearly 10 km, known as the largest karst cave cluster in terms of scale in northern China.

Experts say these caves came into being between 65 million and 450 million years ago through crust movements and corresponding intermittent evolution.