Most national parks celebrate natural beauty found aboveground. At Carlsbad Caverns, the show takes place underground. More than 85 caves underlie the park, two of which — Carlsbad Caverns and Lechuguilla Cave — are among the largest and most magnificent underground formations in the world. In addition to its fantastic rock formations, Carlsbad is also famous for being home to hundreds of thousands of Mexican free-tailed bats, which take flight from the caves and into the desert nightly . . . en masse. The sheer number of these elusive creatures, the massive, whirling, fluttering black blur disappearing into a dazzling southwestern sunset, is an unparalleled wildlife viewing experience.