#cave  an underground enclosure with access from the surface of the ground or from the sea
  supertype:  natural_enclosure__naturalenclosure__enclosure  a naturally enclosed space
  subtype:  cavern  cove.cave  grotto  Lascaux
  part:  floor.Earth's_surface  the bottom surface of any a cave or lake etc.
  part:  stalactite  a cylinder of calcium carbonate hanging from the roof of a limestone cave
  part:  stalagmite  a cylinder of calcium carbonate projecting upward from the floor of a limestone cave
  part:  wall.geological_formation  a vertical (or almost vertical) smooth rock face (as of a cave or mountain)

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