Deep within the passageways that twist and turn at Mammoth Cave National Park the acoustics can be incredible. There is no background noise other than the shuffling feet, soft voices of visitors, and, in some passages, the running or dripping of water. On December 6 those sounds will fade into the background when the park hosts its annual Cave Sing to celebrate the coming holiday season.

While the main attraction is underground at Mammoth Cave National Park, there's quite a bit of history to appreciate above ground. Long before the park was established, homesteads dotted the heavily forested rolling hills. The land that was acquired for the national park displaced small communities that left their mark in the more than 80 cemeteries, churches, and homesteads that can be found within the park's borders.

With more than 150 documented paranormal events, many of them experienced by credible witnesses such as rangers and scientists, Mammoth Cave National Park easily qualifies for the title “most haunted natural wonder in the world.” Park rangers Colleen O’Connor Olson and Charles Hanion have recorded many of the park’s creepiest tales in their book Scary Stories of Mammoth Cave, a must read for anybody intrigued by the park’s supernatural history.

Hoping to leverage the buzz over Ken Burns' 12-hour documentary on national parks, a public television station in Kentucky is preparing to release its own documentary, one focused entirely on Mammoth Cave National Park.