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More than 680 kilometres of passages have been surveyed beneath Kentucky. The figure is taken from National Park Service, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

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Yes. It sits on the Records & Extremes shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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Mammoth Cave is the longest known cave system

More than 680 kilometres of passages have been surveyed beneath Kentucky

Mammoth Cave in Kentucky has been mapped to over 680 kilometres of passage, and survey teams keep adding to it every year. The system formed in limestone that groundwater dissolved away in layers, leaving a maze of dry upper passages and wet lower ones. No other cave comes close to its mapped length.

Mammoth Cave National Park EYELESSF — National Park Service Digital Image Archives · Public domain · source

Where this comes from

National Park Service

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Tags: caves, kentucky, geology

Mammoth Cave is the longest known cave system: the short answers

Where does this come from, and can I check it?: More than 680 kilometres of passages have been surveyed beneath Kentucky. The figure is taken from National Park Service, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a records & extremes fact?: Yes. It sits on the Records & Extremes shelf, one of 1,090 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.