Gerrit Vyn / Rain showers over sagebrush-steppe at the foot of the Sawtooth Mountains. Clark County, Idaho, USA, June.

Espen Bergersen / Two Svalbard reindeer (Rangifer tarandus platyrhychus) Svalbard, Norway, April.

Sven Zacek / Cross-country skiier on a moonlit night admiring the Northern Lights (Aurora borealis), Norway, March 2013.

Peter Cairns / Northern lights (Aurora borealis) over Skagsanden beach, Flakstadoya, Lofoten, Norway. March 2015.

Peter Cairns / Twilight over Flakstad beach, Lofoten, Norway. February 2014.

Dong Lei / Kawakarpo Mountain, view to summit with drifts of snow and the moon setting, Meri Snow Mountain National Park, Yunnan Province, China. May 2010.

Steven Kazlowski / Photographer in front of Northern lights / Aurora borealis glowing brightly over the frozen eastern Beaufort Sea, Arctic National Wildlife Refuge, Alaska Model released.

Erlend Haarberg / Lysefjorden viewed from the Preikestolen (Pulpit rock) on misty summer morning with sun rays shining down, Forsand, Rogaland, Norway.

Kirkendall-Spring / Mount Rainier reflected in tarn above Mystic Lake in Mount Rainier National Park, Washington, USA, August 2014.

Pal Hermansen / Aerial view of river delta, South West Iceland, June 2014.

David Noton / Aurora Borealis (Northern Lights) over the Klondike River, Yukon Territories, Canada, September 2013.

Sandra Bartocha / Scots pine (Pinus sylvestris) trees in snowy woodland in evening sunlight, Potsdam, Germany, January.