WCaveWList of longest cavesWSubterranean riverWAtlantida (cave)WCave castleWCave gateWCave pearlWCave-inWCiolo (Apulia)WCave dwellerWGlacier caveWHospital in the RockWSolutional caveWList of longest caves in the United StatesWPit caveWRock shelterWSolutional caveWSpeleologyWSubterranean waterfallWSukhanand DhamWTunnels in popular cultureWUnderground lakeWYuhuangdong Grottoes