Sinkhole may exhibit a visible opening into a cave below. In the case of exceptionally large sinkholes, such as the Minyé sinkhole in Papua New Guinea or Cedar Sink at Mammoth Cave National Park in Kentucky, an underground stream or river may be visible across its bottom flowing from one side to the other. Sinkholes are common where the rock below the land surface is limestone or other carbonate rock, salt beds, or in other soluble rocks, such as gypsum, that can be dissolved naturally by circulating ground water. Sinkholes also occur in sandstone and quartzite terrains. As the rock dissolves,
Cave Without a Name human contact with the cave began only in the early 20th century, when a small farm animal became trapped in the small external opening of the cave, known as a sinkhole. The cave went largely unnoticed again until the 1920s during the era of Prohibition when a small moonshine distillery was installed in the uppermost cavern. It again fell into obscurity until three local farm children rediscovered the sinkhole in 1935. These children are believed to be the first who actually entered the main chambers of the cave. After the rediscovery, Jim Horn, the original owner of the property decided