I have walked in Jeju’s lava tubes before, which I highly recommend anyone visiting the island to check out and now it appears even more of the lava tube caves are being discovered:

A cave has been discovered on Jeju Island, near a system of lava tubes and other volcanic topography that has already been designated as a World Natural Heritage Site by UNESCO.

The cave was found in Woljeong-ri, Jeju City, near Dangcheomul-donggul, one of five lava tube caves in the heritage site of the Geomunoreum Lava Tube System, according to the World Natural Heritage Jeju, Tuesday.

The heritage authorities have been conducting a drilling operation near the system since April to determine whether there are more undiscovered caves.

The cave, tentatively named “Woljeong Namjimi-donggul,” is 40 to 60 meters away from Dangcheomul-donggul, measuring more than 100 meters long, five meters wide and 1.5 to 2 meters tall. The ceiling of the cave is about 3.5 meters below ground level.

After lava formed the cave, carbonates from the surface were dissolved by rain and flowed down to the cave, creating carbonate products, experts said.

“Cave products such as stalactites, stalagmites, stone pillars and cave corals, are well preserved in the cave, presenting a beautiful view,” said an official of World Natural Heritage Jeju.

Through the drilling operation, the authorities also found that Yongcheon-donggul, which was previously presumed to be about 50 meters away from Dangcheomul-donggul, was just 3 to 10 meters away. “It was also found that the new cave runs parallel with Yongcheon-donggul. The chances are now higher that more undiscovered caves may exist near Yongcheon-donggul in the same direction,” he said.  [Korea Times]