At , Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest () in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition. The cave is named for the canyon through which it is entered, which is named for Agave lechuguilla, a species of plant found there. Lechuguilla is in Carlsbad Caverns National Park, New Mexico. Access to the cave is limited to approved scientific researchers, survey and exploration teams, and National Park Service management-related trips. Exploration history Lechuguilla Cave was known until 1986 as a small, insignificant historic site in the park's back country. Small amounts of bat guano were mined from the entrance passages for a year under a mining claim filed in 1914. The historic cave contained a entrance pit known as Misery Hole, which led to of dry, dead-end passages. The cave was visited infrequently after mining activities ceased. However, in the 1950s, cavers heard wind roaring up from the rubble-choked cave floor. Although no route was obvious, people concluded that cave passages lay below the rubble. Led by Dave Allured, a group of cavers from the Colorado Grotto gained permission from the National Park Service and began digging in 1984. Since the breakthrough into large walking passages occurred on May 26, 1986, explorers have mapped over of passages, making Lechuguilla the eighth-longest cave in the world and fourth-longest in the United States. Lechuguilla was also the deepest known cave in the continental United States at until the exploration of Tears of the Turtle Cave in 2014. Drawn by the cave's pristine condition and rare beauty, cavers come from around the world to explore and map its passages and geology. In May 2012, a team led by Derek Bristol of Colorado climbed over into a dome and discovered several new, unexplored passages, pits, and large rooms. This new section was named "Oz", and many of its features were named after items from The Wizard of Oz. The discovery included a large room measuring long, up to wide, and up to high. It was named "Munchkinland". A pit, named "Kansas Twister", at over from floor to ceiling, is the deepest pit discovered in the park. The team spent eight days mapping Oz, adding the largest distance to the survey since 1989, and bringing the total length to . Geology Lechuguilla Cave offers more than extreme