what is a cavern formed by
A cave is a hollow place in the ground,[1][2] specifically 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, though strictly speaking a cave is exogene, meaning it is deeper than its opening is wide, and a rock shelter is endogene. A cavern is a specific type of cave, naturally formed in soluble rock with the ability to grow speleothems. 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.
A cave or cavern is a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and they often extend deep underground. Because of their uniqueness and beauty, some caves have become very interesting places for tourists and photographers worldwide.evetashka cave is one of the biggest caves in Bulgaria but it is most famous for its amazing history. It is also currently home to nearly 30,000 bats. Devetashka cave is located 18 km (11mi) northeast of Lovech and 2 kilometers (1.2mi) away from the village of Devetaki.