Jeju Volcanic Island and Lava Tubes

The Jeju Volcanic Island and Lava Tubes (Korean: 제주 화산섬과 용암 동굴) is a World Heritage Site in Jeju Province, South Korea. It was inscribed as one of the UNESCO World Heritage Sites in 2007 because of the Geomunoreum Lava Tube System and the exhibition of diverse and accessible volcanic features which are considered to demonstrate a distinctive and valuable contribution to the understanding of global volcanism.

Source: Wikipedia — Jeju Volcanic Island and Lava Tubes (CC BY-SA 4.0)