Feb. 13
The correct answer is: Mammoth Cave National Park. The park, located in central Kentucky, encompasses parts of Mammoth Cave. To date, more than 365 miles of the vast chambers and labyrinths of the cave system have been explored. According to the U.S. National Park service, if the second and third longest caves in the world were joined, Mammoth Cave would still be about 100 miles longer. In 2005, U.S. News and World Report named Mammoth Cave as one of the country’s 20 best vacation spots.