With more than 150 documented paranormal events, the caverns at Mammoth Cave National Park have been called "the most haunted natural wonder in the world." Rangers have reported seeing apparitions resembling slave guides who led cave tours before the Civil War, but the most frequent sighting is of Stephan Bishop, a slave whom the National Park Service website describes as "one of the greatest explorers Mammoth Cave has ever known." Bishop, who's buried in the Old Guide Cemetery not far from the cave, is often seen during the Violet City Lantern Tour, when rangers take visitors through caverns lit only with kerosene lamps.
During the 1800s, Mammoth Cave briefly served as a tuberculosis hospital, and visitors can see the remains of the "consumptive cabins" where patients stayed. Outside one of the cabins is a slab of stone where the bodies of dead patients were place before burial. Today it's known as Corpse Rock, a place where some people claim to have heard phantom coughing.