National Park of Carlsbad Caverns

New Mexico
Established May 14, 1930
46,766 acres (18,925 hectares)

The Chihuahuan Desert, studded with spiky plants and lizards, offers little hint that what Will Rogers called the "Grand Canyon with a roof on it" waits underground. Yet, at this desert's northern reaches, underneath the Guadalupe Mountains, lies one of the deepest, largest, and most ornate caverns ever found.

Water molded this underworld four to six million years ago. Some 250 million years ago, the region lay underneath the inland arm of an ancient sea. Near the shore grew a limestone reef. By the time the sea withdrew, the reef stood hundreds of feet high, later to be buried under thousands of feet of soil. Some 15 to 20 million years ago, the ground uplifted. Naturally occurring sulfuric acid seeped into cracks in the limestone, gradually enlarging them to form a honeycomb of chambers. Millions of years passed before the cave decoration began. Then, drop by drop, limestone-laden moisture built an extraordinary variety of glistening formations—some six stories tall; others tiny and delicate.

Cave scientists have explored more than 30 miles (48 kilometers) of passageways of the main cavern of Carlsbad, and investigation continues. Visitors may tour three of these miles (five kilometers) on a paved trail. Slaughter Canyon Cave provides the hardy an opportunity to play caver, albeit with a guide. The park has more than a hundred other caves open primarily to specialists.

Some visitors think the park's most spectacular sight is the one seen at the cave's mouth. More than a quarter million Brazilian (Mexican) free-tailed bats summer in a section of the cave, and around sunset they spiral up from the entrance to hunt for insects. The nightly exodus led to the discovery of the cave in modern times. Around the turn of the 20th century, miners began to excavate bat guano—a potent fertilizer—for shipment to the citrus groves of southern California. One of the guano miners, James Larkin White, became the first to explore and publicize the caverns beyond Bat Cave.