A sinkhole occurs when an area of ground collapses, creating holes that can swallow up swimming pools, roads, buildings and people. The United States Geological Survey describes three different categories of sinkholes based on how they are created: dissolution, cover-subsidence and cover-collapse sinkholes. In all three, erosion of land is caused by minerals washed away by water over time. The most dangerous type of sink hole, and the ones we usually see in the news, are cover-collapse
Neversink Pit is a limestone sinkhole in Alabama, and it’s one of the most-photographed sinkholes in the world because of its beautiful fern-covered ledges and waterfalls. The hole is about 40 feet wide at the top, but it expands to 100 feet at its bottom, which is 162 feet from the ground. Neversink is home to bats and several rare and endangered fern species.