An extraordinary cave network, never seen by human eyes, has been discovered in the depths of a US national park.
The eerie blue pool found hidden inside has been described as a "wonderous sight" by park employees at the Carlsbad Caverns National Park in New Mexico.
It followed an expedition into what are called "virgin" cave passages in the park, long renowned for its complex cave structures filled with wax-like stalactite rock formations.
Now explorers have discovered something uniquely remarkable – an isolated pool of milky-blue water untouched by humans, 700ft below ground.
Carlsbad Caverns announced the discovery on Facebook on June 2020, calling the site found within Lechuguilla Cave “completely pristine”.
Geoscientist Max Wisshak, who led the expedition wrote: "The edges beneath this pool appear to be ‘pool fingers’, which could be bacterial colonies that have evolved entirely without human presence."
Wisshak led the expedition in October 2019, alongside a team of specialist explorers who were given special permission to explore beyond a body of water known as the "Lake of Liquid Sky" which was discovered in 1993.
He said: "The goals of this expedition have been a long time in the making. Rest assured… The team took special precautions to ensure there were no contaminants introduced to these pools of water."
He posted a picture shows the strange alien-looking sight, comprising white frosted rock filled with a strange glowing milky-blue substance said to have been untouched for millennia.
Rodney Horrocks, Chief of Natural and Cultural Resources at Carlsbad Caverns National Park told local media: "This pool has been isolated for hundreds of thousands of years and had never seen light before that day."
Wisshak added: "Such untouched pools are scientifically important because water samples are relatively free of contaminants and the microbial organisms that may live in those pools are only those that belong there."
"Contamination can occur from the surface above the cave, but in case of Lechuguilla Cave, that’s not a big issue, since it is situated in a well-protected wilderness area. It can also occur via aerosols in the air. However, a newly discovered pool in Lechuguilla Cave is about as pristine as it gets."
The pool is estimated to be about a foot wide, 2 feet long and several inches deep and although it looks cloudy, the water is actually crystal clear and most likely formed of ancient filtered rainwater.
