what is a cave in geography
A cave or cavern is a hollow place in the ground, especially a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground.The word cave can also refer to much smaller openings such as sea caves, rock shelters, and grottos. Speleology is the science of exploration and study of all aspects of caves and the cave environment.Visiting or exploring caves for recreation may be called caving, potholing, or spelunking. The cave system with the greatest total length of surveyed passage is Mammoth Cave in Kentucky, USA, at 643 km (400 mi). 2  This record is unlikely to be surpassed in the near future, as the next most extensive known cave is Jewel Cave near Custer, South Dakota, USA, at 267 km (166 mi).