Sometime around 1798 a man named John Houchins shot and wounded a bear in the Kentucky wilderness. He followed it to the entrance of a cave that turned out to be much bigger and more mysterious than the others that abounded in the region. The cave soon started drawing visitors, eventually including such luminaries as Ralph Waldo Emerson and Jenny Lind, the “Swedish Nightingale.” Then, as now, the cave was known for its beautiful and haunting rock formations, with names like the Church, Fat Man’s Misery, Frozen Niagara, the Drapery Room, and the Rotunda. Equally fascinating were ancient skeletons and Indian relics preserved by the cave’s cool temperatures and low humidity (conditions that have also permitted the survival of ceiling graffiti written in candle soot, some from the early nineteenth century).

Mammoth Cave and the ground above it were declared a national park in 1926, and in 2003 the photographer Raymond Klass lived in the park for three months, exploring its 365 miles of mapped tunnels (there may be another 600 miles unmapped) as well as the forest above. More than a hundred of his photographs, covering everything from ancient lava flows to tree-covered hills to acorns, squirrels, and snails, along with excerpts from his journal, can be found in Mammoth Cave National Park: Reflections , by Raymond Klass (University Press of Kentucky, 144 pages, $25.00).