The Guadalupe Mountains of southeastern New Mexico host some of finest caves in the world, including Carlsbad Cavern and Lechuguilla Cave. These caves formed differently than most caves: they were dissolved by sulfuric acid, not carbonic acid, where the sulfuric acid was derived from the oil and gas fields of the nearby Delaware Basin. First we explain the Capitan Reef in the Guadalupe Mountains so as to give you the geologic background to understand why Carlsbad Cavern is so deep and why the Big Room is one of the largest cave rooms in the world. We will also cover the spectacular mineralogy of the caverns and tell you how its cave minerals and formations (“speleothems”) were deposited. The lecturer has worked as a geologist in Carlsbad Cavern and the Guadalupe Mountains for over 25 years, and has published the books: Cave Minerals of the World, Geology of Carlsbad Cavern and Other Caves of the Guadalupe Mountains, and Geology of the Delaware Basin: Guadalupe, Apache, and Glass Mountains. This class is intended to greatly enhance your next visit to Carlsbad Caverns and Guadalupe Mountains National Parks.