Discover the vast chambers and complex labyrinths of Mammoth Cave. Signifying its cultural and historic significance, Mammoth Cave has been designated a UNESCO World Heritage Site. The Park is home to the longest network of caves in the world, with over 400 miles to explore. Above ground, the pristine and protected woodlands of the Green River Valley provide a 52,000 acre wildlife refuge with more than 80 miles of trails that are perfect for hiking, horseback riding, biking, boating and fishing.