The sponges and sea life that formed a reef in this sea over the eons now comprise the mountains surrounding the caverns today. After the inland sea evaporated, water continued as the main catalyst in the cavern's formation. Rainwater percolating down through the limestone mixed with hydrogen sulfide moving up from oil and gas deposits far below, creating a mild sulfuric acid solution. Over time, the acidic water eroded and enlarged the cracks in the rock to form the caverns. Today, Carlsbad Caverns' many chambers have grown to over 30 miles of explored caves, with its largest chamber, the Big Room, large enough to hold 14 football fields.
Water is also the force that has decorated the caverns.
Dripping water slowly dissolved minerals in the rock and carried it in solution to be deposited elsewhere, forming the colorful stalactites and stalagmites, delicate draperies, soda straws, and other fanciful formations that make Carlsbad Caverns a world renowned destination. Paved trails and electric lights allow easy exploration of the formerly dark and dangerous passages. Access to the caverns is provided by both a trail through the natural entrance, or by an elevator, that whisks you effortlessly 750 feet underground to the cavern floor. There are two self-guided tours of the cave, each about an hour to an hour and a half long. I prefer to combine the two tours by entering the cavern through the Natural Entrance Route, descending the steep switchbacks and wooden staircases into the increasing gloom, past the bat cave and evermore-fantastic rock formations.