The darkness is so complete that I can close my eyes, open them again, and see no difference. For seemingly long moments that might have been a few seconds, our group of 25 falls silent. Only the sound of dripping water penetrates the quiet as cave formations continue growing, drop by drop.
When ranger Ben Boime relights his lantern, a single candle in a glass-and-wood box not unlike what the first cave explorers would have carried, the entire wall illuminates. To eyes adjusted to total blackness, this token of light casts a glow like a flood.
We’re 830 feet underground at Carlsbad Caverns National Park, deep into the King’s Palace Tour. The Big Room, the massive central cavern that sees 500,000 visitors each year, has been open to self-guided tours since the 1970s—after so many hundreds of people overwhelmed daily ranger-led tours that the front of the line never saw its end. But
