The Light in Mammoth Cave

In 2023, a park ranger at Mammoth Cave in central Kentucky led a group of tourists deep into the longest known cave system on earth — over four hundred miles of mapped passageways beneath the rolling hills. At one point, nearly three hundred feet underground, the ranger asked everyone to switch off their headlamps and phones. Total darkness. Not the darkness of a bedroom at night, but a darkness so absolute that visitors instinctively reached for the cave wall just to confirm they still existed in physical space.…