The real attraction, though, is under their shoes.
The explorers have reached Snowy River -- thought to be the longest continuous cave formation in the world.
"I think Snowy River is one of the primo places underground in the world and there's still so much left that we haven't discovered. ... We don't even know how big it is," said Jim Goodbar, a cave specialist with the federal Bureau of Land Management.
The survey expedition by members of the Fort Stanton Cave Study Project in early July added several thousand feet to the measurement of the spectacular formation, which is at least four miles long. The explorers who have been following the passage under the rolling hills of southeastern New Mexico say there's still more of Snowy River to be discovered.
The few who have walked on the formation say they've seen nothing else like it. Early studies point to its uniqueness: Already, some three dozen species of microbes previously unknown to science have been uncovered.
New Mexico's two U.S. senators are pushing for Congress to designate Fort Stanton Cave and Snowy River as a national conservation area. The designation would protect the area from such activities as mining that threaten the water flows that created the cave. It also might generate funding for scientific research. (...)"
Full text: Discovery.com