What is a Cave?

 
A geological formation consisting of an underground enclosure with access from the surface of the ground or from the sea.
 

What is an Example of a Cave?

 
Mammoth Cave National Park, located in southern Kentucky features the world’s longest recorded cave system. In all, more than 360 miles of caves have been mapped and explored. Scientists believe there may be another 600 miles of caves yet to be explored. In addition to the amazing cave system, the park is located along the Green River, one of the most biologically diverse rivers (in terms of fish and invertebrates) in North America. Before Mammoth Cave became a national park, local farmers who owned nearby tracts of land waged what was called the Kentucky Cave Wars, a bitter competition between land owners to lure tourists to caves on their properties. "Cappers," as they came to known as, would trick tourists into believing the main caves were closed and would direct them toward lesser caves on their own property.