Longest caves

The following is a list of the world's 10 longest caves per length of documented passageways. Many passageways are still being discovered; this list is based on the latest verifiable data.

Caves are found around the world. The largest form in areas of karst landforms whose rocks erode easily and create caves. Preferable conditions for cave formation are adequate precipitation, enough plants and animals to produce ample carbon dioxide, and a landscape of gentle hills which drains slowly. The highest concentrations of long caves in the world are found in the Pennyrile of Southern Kentucky, United States, in the Black Hills of South Dakota, United States, and in the Yucatán Peninsula, Mexico.

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