250 million years ago, the Guadalupe Mountains — in what is today known as New Mexico, U.S. — were the ancient shoreline of a vast inland Sea that covered a great area of plains states. Today, much of New Mexico is covered with parched desert lands, though there are many features in this land that are still remnants of that long lost sea. The Carlsbad Caverns are one of the most impressive features created by the retreating waters from long ago. The caverns are an immense series of single caves, or “rooms,” which follow the path of the original water’s retreat through the hard limestone and soft clay and dirt. Not only is this one of the largest cave systems that has been discovered in America, the details of this system of caves is what sets it apart from any other.

Carlsbad Caverns Entrance

This winding switchback into the mouth…