Ryongmun (Dragon Gate) Cavern is an expansive limestone cave formed 480 million years ago by erosion from rainwater. The subterranean system is 6km long, broken into two major sections spanning over 30 wings. As far as caves go, Ryongmun Cavern is genuinely impressive and the local guides can be best described as cheeky and entertaining, with a repertoire of lewd connotations and mythical legends up their sleeve as you pass notable stalagmites and stalactites. Bring a jumper as it’s always cold underground!
Nearby, Paengyong Cavern and Songam Cave are alternative cave systems, but are less impressive than Ryongmun Cavern and are rarely visited by non-enthusiast foreigners.