Scratching the surface

Hidden below southeastern New Mexico's Chihuahuan Desert is one of the world's most extensive subterranean landscapes, Lechuguilla Cave. Named for a type of agave plant native to the area, Lechuguilla stretches more than 150 miles in length, making it the eighth-longest explored cave in the world. Naturally, these pristine, deep caverns have attracted adventurous scientists from all over the world to research and explore the great unknown. Discovered in the 1980s at the edge of Carlsbad National Park, the full extent of this underground wilderness is still yet to be realized. Once a month, one team is permitted by the Park Service to conduct an ongoing investigation into the cave. The explorers typically spend a full week underground, making for a logistical, staging and sensory adventure not for the faint of heart. Here's look at a recent expedition: