These Northern Lights “rainbows” have turned the sky greener than the Earth below. Vitaly Istomin, 26, spent several nights in freezing conditions under the stars in northern Russia’s Khibiny Mountains to capture the aurora’s “rainbows”. (Photo by Vitaly Istomin/Caters News Agency)

“After an afternoon of hiking and exploring the caves of Rhossili Bay, West Glamorgan, we caught the sun breaking through the clouds”. (Photo by Megan Warren-Davis/The Guardian)

19 individually themed and hand crafted art suites have been newly designed by creatives from across the world – from a swedish artist who made a giant snow elephant in the room, to a french team who fused snow, ice and disco into a groovy sleeping experience. Each year, the hotel creates a new series of artist-designed accommodation spaces that add to the existing landscape of private rooms. (Photo by Icehotel.com/Exclusivepix Media)

Pupils participate in a calligraphy contest to celebrate the New Year in Tokyo January 5, 2016. Over 3,000 calligraphers who qualified in competitions throughout Japan wrote resolutions or wishes onto paper sheets during the annual contest that marks the start of the new year, according to organizers. (Photo by Thomas Peter/Reuters)

A photographer could bear-ly believe his eyes when a bear started waving at him. The friendly animal wandered to the front of his enclosure before sitting back in full view of zoo guests. He then lifts his powerful paw and excitedly waves in an almost human-like way at his new audience. The hilarious encounter was captured by keen photographer Andrey Slepnev, 31, while on a trip to Madrid Zoo, Spain on March 24, 2016. (Photo by Andrey Slepnev/Caters News)

The series of shots show the bare steel infrastructure of the Bushfield army training camp near Winchester which was in operation during World War Two and was used to train Royal Green Jackets recruits in the sixties. The spectacular images were taken by an urban explorer who wished to remain anonymous. Here: A railway siding in Wiltshire, UK where ammunition was transferred by tunnel to an underground storage facility. (Photo by MediaDrumWorld.com)

An Iraqi Muslim woman walks past Christmas decorations for sale in the Shiite holy city of Najaf on December 17, 2015. (Photo by Haidar Hamdani/AFP Photo)

South Korean traditional bow artisan Kwon Yeong-Hak works on a bow in his workshop in Yecheon-gun, Gyeongsangbuk-do, South Korea, 26 February 2015. Kwon Yeong-Hak still crafts his bows in the traditional way, carrying on a four-generation family business. The Gakgung bow, of which Kwon is one of the last remaining artisans, is unique to Korea, and is constructed with a variety of materials, including water buffalo horn, oak, bamboo and cattle spinal sinew. A ban on the import of water buffalo horns has put the Gakgung tradition at risk. (Photo by Jeon Heon-Kyun/EPA)