A subterranean world of interconnected salty lakes that may support a microbial ecosystem lies beneath one of Antarctica's most barren and lifeless regions, scientists have discovered.
The aquifer network extends to a depth of up to 1,148ft (350m) below the McMurdo Dry Valleys, the coldest and driest desert on Earth.
A hoop-like electromagnetic sensor suspended beneath a helicopter was used to map the hidden subsurface. WORDS: PA.
Measurements of electrical resistivity revealed extensive, connected bodies of liquid salty water deep beneath the region's glaciers and lakes.
The network stretched from the coast for a distance of at least 7.5 miles (12km) inland.
US lead researcher Dr Jill Mikucki, from the University of Tennessee, said: "It may change the way people think about the coastal margins of Antarctica.
"We know there is significant saturated sediment below the surface that is likely seeping into the ocean and affecting the productivity of things that feed ocean food webs. It lends to the understanding of the flow of nutrients and how that might affect ecosystem health."
The findings, published in the journal Nature Communications, may shed light on how Antarctica has responded to climate change, said the researchers.
They might also help scientists understand whether similar conditions could exist elsewhere in the solar system, especially beneath the surface of Mars.
Cold and vegetation free, the Dry Valleys represent the nearest thing on Earth to a Martian environment.
Evidence suggests that the salty groundwater exists at below-freezing temperatures within the range tolerated by microbial life.
The McMurdo Dry Valleys, situated along the Ross Sea coastline and discovered by polar explorer Robert Scott in 1903, is the largest region in Antarctica not covered by an ice sheet.
It consists of an arid expanse of mostly dirt, small rocks and large boulders, dotted with a few frozen lakes.
Co-author Professor Ross Virginia, from Dartmouth College in New Hampshire, said: "This fantastic new view beneath the surface will help us sort out competing ideas about how the McMurdo Dry Valleys have changed with time and how this history influences what we see today."
Ten of the best: Ice hotels
Incredible underground lake system found under Antarctica
If remote and romantic are two of your musts, then this newcomer to the ice hotel scene should suffice. 2000m above sea-level, and accessed only by cable car, the Lake Balea ice hotel is a 10-14 room igloo which is reconstructed out of the frozen lake every season. Sleeping arrangements are surprisingly Dr Zchivago-esque with rich fur stoles (and thermal sleeping bags) arranged on top of your ice mattress.
There's also an ice church close-by for those who might feel inclined to prayer for warmer climes and an ice bar for those more content with a hot toddy before bedtime.
Stay in an igloo made for two in this low-key, budget-friendly option. What it lacks in style, the snow pods at Kakslauttanen make up for in price - coming in considerably cheaper than many of its rivals. The package here can also include a wide-range of snow activities - from a Winter safari to ice fishing and snowboarding, as well as being one of the best located to catch the Northern Lights. The resort's glass snow domes offer a more luxe option - the futuristic forrest village of geodesic domes is a sight to behold.
Kipping in constant temperatures of between -4C and -7C can be surprisingly comfortable when you're wrapped up in reindeer hide, although the Alta Snow Hotel recommends that your bring your woollen undies as a fall-back. A smaller version of Sweden's ice hotel, the Alta is known for its intricate ice sculptures, but it's the unique opportunity to watch the Aurora Borealis from right outside your igloo door that's the real selling point here.
Canada's only ice hotel celebrates its 10th anniversary this season (January to March) with its most ambitious reconstruction yet; with the site set to include a vast multi-media igloo and an adult-sized snow slide to boot. The concept for the Hotel de Glace is a combination of indigenous Inuit igloo construction and Nordic influences; which are echoed throughout the 36 unique rooms and suites. Thankfully an outdoor spa, including that all important sauna, on hand to help keep your spirits up, but for those who miss their home comforts Suites come with their own log fireplace (but let's face it: heating's cheating).
A snow hotel is one thing, but it pales into comparison next to the effort put into create an entire village. In the Finnish resort of Yllas, besides the 15 bedrooms and suites, there is a restaurant, a bar, lobby and outdoor slide and sculpture park. In the hotel, the ambient lighting takes its inspiration from the Northern Lights and you can counter-balance the potential frost bite with a morning sauna and a hot berry juice.
Honeymooning in -5 temperatures may not be everyone's idea of a romantic getaway but booking the honeymoon suite at the Lumilinna Snow Castle as least shows some imagination; the elaborate castle carved from ice is fit for any snow queen. The Snow Chapel will also oblige with a winter wedding, should you feel particularly swept away.
If its a holiday of extremes you're after, how about dipping your toes in the Med one minute and then two hours later, wrapping up against sub zero temperatures? In the Andorran ski resort of Grandvalira you can spend the night in an Igloo village run by Iglu Dorf - and in the day head back down to Barcelona in just a couple of hours. There's mulled wine and fondue on-hand, as well as a hot tub to keep you toasty.
Combine skiing in the Alps with an overnight stay at the very reasonably priced Schneedorf - Austria's first foray into the realms of ice hospitality and one of many strange lumpy white domes now populating the Alpine landscape. Furnished simply and with flourishes of snow sculpture, the hotel is perfect for skiers who want to be up and at it early, as well as the less-active who just want to soak up the gluhwein from the warm safety of the hot tub.
The best way to approach the remote Kirkeness ice hotel is with the spirit of an explorer - because just reaching the location in the northern most tip of Finland, right up on the border with Russia, is some expedition in itself. Enduring a night's sleep in sub-zero temperatures is a whole other matter; good job there's an ice bar on stand-by for the obligatory shot of dutch courage before you bunk down for the night.
The original ice hotel in Jukkasjarvi is as much art installation as it is an experience. Welcoming its first overnight guests in 1992 the Ice Hotel continues to grow its ambition - creating an entire adventure based around their location 200 kilometers above the Arctic Circle. Recreated every winter from the frozen River Torne, with a new collective of artists and designers, the hotel takes on an entirely new theme and is considered the most luxurious in its category (the resident's Absolut Vodka bar has become an institution in itself). Visitors arriving in early December will see the new hotel start to take shape, with the construction taking several weeks to complete.