We drove to the cavern during a now practically chilly (compared to Roswell) 109 degrees. We arrived at the Carlsbad Caverns National Park visitor center, which stands over the cavern. A hot, dry desert wind gusted over the mountain top. We made sandwiches. The bread instantly grew hard and crusty in the hot wind, cutting the roofs of our mouths ala Captain Crunch.

The desert here is a dry, dusty place with only patches of agave, sagebrush and no vegetation taller than your knee -- all tan and white, with hints of gray and dusty brown stretching into the horizon. At the base of this mountain on which the visitor center sits stretches an unbelievably flat plain all the way to the horizon. At night, this plain is as dark and flat as the ocean. Tiny lights from a few houses in the sea of darkness could just as easily be ships adrift on the placid waters.

We secured tickets for the King's Palace Tour, one of several ranger-led tours available. The cave was a cool, dark 56 degrees. The ranger led us through room after room of towering stalagmites, columns, and draperies. Cavern ceilings soared above us. Never have I been in a more tremendous cave. Water dripped in the vast hollows of the cavern.

When we'd looped around, we continued on by ourselves, hiking through the "Big Room" portion of the cave. This is far more than a "Big Room," as it winds around for more than 8.2 acres through even more stunning rooms. The viewpoint for Lower Cave dropped away ninety feet straight down. A wire and wood ladder from the late 1890s hung down into a dark hole leading to Lower Cave, evidence of the cave's early explorer, Jim White.

We peered into the Bottomless Pit -- the portion of the cave that has the most vertical clearance. Reluctantly we emerged from this exploration, blinking into the bright daylight. We hiked out to the large Natural Entrance to await the famous mass exodus of the Mexican free-tail bats.

The cavern is home to more than 600,000 Mexican free-tails, and they all stream out in a matter of minutes, creating an undulating black cloud in the purple desert sky. We heard a whoosh of wings, and suddenly bats began spiraling out of the large, black mouth of the cave. They must fly out in a spiral in order to get lift. In a great outpouring they filled the sky, dipping and diving, already catching insects.

We sat and watched until it grew too dark to see them, and still they poured out of the cave. They flitted and fluttered just over our heads. The stars came out, glittering and intense in the dark desert sky.

Tomorrow...further exploration of the mysterious caverns as we hike in through the Natural Entrance...