Hwanseongul

Hwanseon Cave (환선굴) is a cave located in Gangwon province, South Korea. == Description == Hwanseon Cave is the longest known limestone cave in Korea, with of known passages and a total suspected length of , of which are visited by over 1 million people per year. In 1966 the South Korea government designated this cave and a neighboring cave not open to the public, Gwaneum cave (관음굴), National Monument 178. Hwanseongul was opened to the public in 1997.