The world's longest caves. The cave system called Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed is truly mammoth. 400 miles of explored and mapped caves with another 600 supposedly yet to be mapped and connected. The park was established as a national park on July 1, 1941. It became a World Heritage Site on October 27, 1981, and an international Biosphere Reserve on September 26, 1990.

The national park is around 6.5 hours from Chicago, with the closest cities being Nashville, TN and Louisville, KY both about 1.5 hours away. The best way to explore the park is by staying at the Mammoth Cave Hotel, the only lodge inside the park. The hotel is connected via a bridge to the visitor center and has a restaurant in-house.

The park rangers offer multiple tours of the cave, covering over 12 miles and with varying difficulty. Two of the best, moderate level tours, are the New Entrance Tour which includes the Frozen Niagara section and the Historic Tour which takes you on the original tour. Both are 2 hour treks.

If the raw power of water is showcased above ground at the Grand Canyon, the slow, grinding, yet forceful nature of water is showcased perfectly at the Mammoth Cave. Incredible!