At Hwalok Cave, or Jade Cave, visitors have a unique opportunity to explore one of Asia’s biggest formore mines by foot and by kayak. This cave was carved out over centuries by Korean miners and is 8.2-kiliometers long with its highest depth reaching 711 meters. Visitors can explore the cave by foot on a leisurely stroll through the 800-meter-long LED-illuminated passageways and can also hop in a clear-bottom kayak for access to other parts of the cave.