Hyeopjaegul and Ssangyonggul Lava Caves are thought to have already been developed as a result of an eruption of Mt Hallasan around twenty five million a long time ago, and are considered to happen to be under sea level at some time as a result of existence of fossilised abalone https://fernando10c9k.ageeksblog.com/26514192/the-definitive-guide-to-jeju-paradise-lsland