Carlsbad Cavern

Carlsbad Cavern is a show cave in the Guadalupe Mountains. The Big Room inside covers 8.2 acres, and the National Park Service describes it as North America’s largest readily accessible cave chamber. It’s a standout visit because you can walk through a room on a remarkable scale and choose between a steep entrance hike and elevator access.

The self-guided Big Room Trail is a relatively level 1.25-mile loop that takes about an hour and a half; a 0.6-mile shortcut averages about 45 minutes. The Natural Entrance Trail descends about 750 feet on a steep route. You can take the elevator from the visitor center to avoid that descent, or walk down and use the elevator back to the surface.

The Natural Entrance route isn’t accessible. Only designated portions of the Big Room route are wheelchair accessible, and the walking surface can be wet, slippery and uneven enough to need assistance. The cave is dim and drips can leave parts of the path wet, so shoes with good traction help.

The Big Room path winds past tall columns, draperies and other formations across a chamber so broad it can be hard to take in at once. The Natural Entrance route has its own named features, including Devil’s Spring, the Whale’s Mouth and Iceberg Rock. If you make the Natural Entrance descent, allow time to notice how the formations change along the way instead of treating it as just a way to reach the Big Room.

For a photo in the Rookery, keep part of the walkway in the frame; it gives the towering formations a useful sense of scale.

The rock began as a fossil reef beneath an inland sea about 265 million years ago. The cave itself formed much later, when water carrying hydrogen sulfide mixed with oxygen-bearing groundwater and created sulfuric acid that dissolved the limestone. Gypsum, clay and silt left behind help tell that story. Cave formation largely stopped about four million years ago, though later rockfalls and mineral deposits continued to shape passages.

Long before modern tours, Mescalero Apache and Zuni Pueblo people knew the cave area; cooking pits and a cave painting remain near the Natural Entrance. The evidence doesn’t establish that they explored deep passages. In 1898, 16-year-old cowboy Jim White saw bats streaming from the entrance and thought the cloud was smoke. He later climbed into the cavern on a homemade ladder and named features such as the Big Room and Devil’s Spring.

Guano mining began in 1903. The site became a national monument in 1923 and a national park in 1930. The Natural Entrance had wooden stairs by 1925; the first elevator started operating in 1932.

The cave’s Brazilian free-tailed bats emerge around dusk, and cave swallows have nested just inside the entrance since 1966. The separate Bat Flight Amphitheater is where visitors watch the evening emergence; it’s a different stop from the cavern walk.