This National Park Is Home to the Longest Cave in the World—and Only 426 Miles Have Been Explored So Far #Travel Here’s how to plan a trip to Mammoth Cave National Park.

Here’s how to plan a trip to Mammoth Cave National Park.<div class="media_block"><a href="https://www.travelandleisure.com/thmb/zWo4zjYAdJlaMr9qoltLn7DxRZk=/filters:no_upscale():max_bytes(150000):strip_icc():format(jpeg)/TAL-mammoth-park-enterance-MAMMOTHCAVEGUIDE0126-baf43a883dff401e8eacc8205611e9ce.jpg"><img src="https://www.travelandleisure.com/thmb/zWo4zjYAdJlaMr9qoltLn7DxRZk=/filters:no_upscale():max_bytes(150000):strip_icc():format(jpeg)/TAL-mammoth-park-enterance-MAMMOTHCAVEGUIDE0126-baf43a883dff401e8eacc8205611e9ce.jpg" class="media_thumbnail"></a></div>