If you’ve ever been intrigued by the subterranean world, plan a stay at the Horse Cave KOA. It lies in the heart of one of the most significant cave regions on the planet. Beneath the area’s rumpled hills, eons of dripping and flowing waters have worn through the limestone bedrock, creating a maze of underground rooms, rivers and sinkholes. Nearby Mammoth Cave National Park preserves the world’s largest known cave system.