Deep within New Mexico’s Fort Stanton Cave, the Fantastic Snowy River Passage, winds its way through the underground.

Discovered in 2001, after over 100 years of exploration in the Main Passage of Fort Stanton Cave, Snowy River has been surveyed by the Fort Stanton Cave Study Project at over 4 miles with no end in sight.

The passage was named for the subaqueous calcite formation that lines the floor of the passageway, and scientists now believe it may be the longest continuous calcite formation in the world.

The story of its discovery, the potential for future exploration, and the scientific discoveries yet to be revealed makes this one of the most exciting finds of the 21st century.