Norway's violinist Nils Oekland tests his instrument built of ice on Jan. 10, 2009 in Geilo, for an ice instrument festival. (JOHN HUGUES/AFP/Getty Images)

We build snowmen, igloos, and even hotelsout of snow and ice, but it takes a bit more ingenuity to carve musical instruments.

Now in its 9th year, the Norwegian Ice Music Festival hosted in the mountain town of Geilo celebrates the beauty and sounds of the natural world with concerts played entirely on ice. The festival was developed by Terje Isungset and Pal K Medhus and begins with the first full moon of the new year.

"The majority of the ice that we use comes from the lakes around and we have to go up by snowmobile … and cut the ice out, pull it out and bring it back to the venue in Geilo," said American ice sculptor Bill Covitz in an interview with NPR. Covitz has sculpted everything from cellos to ice horns, which the musicians then tune as much as possible.

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The difficulty with making music from ice is the weather and the act of playing. Wind instruments in particular pose problems because the musician's breath will warm and melt the interior of the instrument.

"Because the sound of the ice changes with time and temperature, the music is always improvised," said Isungset, one of the founders, in an interview with ABC. "While the rhythm may be repeated, no piece ever sounds the same."

The festival also has a strong focus on nature, said Atlas Obscura, and aims to leave the smallest environmental footprint possible, despite the growing crowds who come to see the unique performances.

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Circa 1911: Norwegian explorer Captain Roald Amundsen, the first man to reach the South Pole, inspecting ice fields near a glacier in the Atlantic Ocean. (Keystone/Getty Images)