Gwangmyeong Cave is at Gwangmyeong, Gyeonggi-do, Republic of Korea. In the early 20th Century, it was used for mining gold, silver and zinc. The City of Gwangmyeong took safety measures for the closed mine and turned it into a tourist destination in 2011. Its natural environment, particularly its incredible geological features, attracts tourists to the city. [Photo by Huang Shuo/chinadaily.com.cn]