Ismaele Tortella / Northern gannet (Morus bassanus) colony, chick climbing back into nest, with the midnight sun, Norway, July

Espen Bergersen / European elk / Moose (Alces alces) photograped in midnight sun. Troms, Northern Norway. June

Orsolya Haarberg / Flowering cottongrass (Eriophorum angustifolium) in a wetland area with midnight sun. Sjaunja Nature Reserve, Laponia World Heritage Site, Swedish Lapland, Sweden. July 2013.

Ole Jorgen Liodden / Svalbard Reindeer (Rangifer tarandus) grazing in midnight sun. Spitsbergen, Svalbard, August.

Ole Jorgen Liodden / Polar Bear (Ursus maritimus) in arctic ice landscape backlit by midnight sun. Nordaustlandet, Svalbard, August.

Steven Kazlowski / Northern lights (Aurora borealis) across the night sky as the late summer midnight sun travels eastward, over the Beaufort Sea, off shore from the 1002 area of the Arctic National Wildlife Refuge, Ala...

Steven Kazlowski / Inupiaq / Inuit man hold his hand under the midnight sun in the Chukchi Sea, off shore from the arctic village of Barrow, Alaska, USA. April 2009

Wild Wonders of Europe / Widstrand / Herring gull (Larus argentatus) close up in flight, in midnight sun, Flatanger, Nord Trndelag, Norway, August 2008

Theo Allofs / Large icebergs at midnight, end of June, mid-summer night, Greenland

Staffan Widstrand / Coastal landscape and small iceberg in midnight summer sun, Qaanaaq, Greenland

Seppo Valjakka / Stoat in midnight sun (Mustela erminea) northern Finland

Jim Brandenburg / Inuits dog sledding in midnight sun, Ellesmere Island, Nunavut, Canada

Tui De Roy / Broken fast ice under midnight sun and impending storm, Edward VIII Bay, Kemp Coast, east Antarctica

Tui De Roy / Emperor Penguin (Aptenodytes forsteri) large chick on fast ice, midnight sun in austral spring, No-name Rookery, Princess Martha Coast, Weddell Sea, Antarctica

Michio Hoshino / Caribou (Rangifer tarandus) of the Porcupine Herd climb Brooks Range foothills at midnight during migration, Alaska

Espen Bergersen / Sperm whale (Physeter macrocephalus) and midnight sun. Outside Andoya, Northern Norway. November.

SCOTLAND: The Big Picture / The most northerly point in the British Isles, Muckle Flugga on Unst, Shetland, Scotland, UK, June.

Stefan Christmann / Southern ocean in middle of night, in summer. Atka Bay, Antarctica. February.

Werner Bollmann / Barn swallows (Hirundo rustica) calling, silhouetted in midnight sun, Oland, Sweden, June.

Werner Bollmann / Barn swallows (Hirundo rustica) calling, silhouetted in midnight sun, Oland, Sweden, June.

Ashley Cooper / Colourful houses in Illulisat, UNESCO World Heritage Site, Greenland, July 2008.

Ashley Cooper / Igloos outside the Arctic Hotel, Ilulissat UNESCO World Heritage Site, Greenland. July 2008.

Sandra Bartocha / Midnight Sun, Varanger Peninsula, Norway, June 2013.

Pal Hermansen / Storage house for Eider duck down before cleaning , with midnight sun. Lanan, Vega islands UNESCO World Heritage Site, Northern Norway, Highly commended in the Man and Nature Category of Terre Sauvage...

Pal Hermansen / Common eider (Somateria mollissima) males ducks on beach at night, Patreksfjordur, Iceland, June. Winner of the Portfolio Award of the Terre Sauvage Nature Images Awards Competition 2017.

Ingo Arndt / Midnight sun over icefield in late winter, Svalbard, Spitsbergen, Norway, April. Taken on the day of the first midnight sun of the year.

Ingo Arndt / Polar Bear (Ursus maritimus) on icefield under first midnight sun in late winter, Svalbard, Spitsbergen, Norway, April Taken on the day of the first midnight sun of the year.

Ingo Arndt / Midnight sun in late winter, Svalbard, Spitsbergen, Norway, April Taken on the day of the first midnight sun of the year.

Ingo Arndt / Drifting ice under midnight sun in late winter, Spitsbergen, Svalbard, Norway, April Taken on the day of the first midnight sun of the year.

Ingo Arndt / First midnight sun in late winter at Isfjorden, Svalbard, Spitsbergen, Norway, April Taken on the day of the first midnight sun of the year.

Ingo Arndt / First midnight sun in late winter at Isfjorden, Spitsbergen, Svalbard, Norway, April Taken on the day of the first midnight sun of the year.

Andy Trowbridge / Tourists watching the sky at midnight at Nordkapp. Nordkapp is the northernmost point to which one can drive a car in Europe. Nordkapp, Finnmark, Norway. July 2014.

Ole Jorgen Liodden / Polar bear (Ursus maritimus) with midnight sun, Svalbard, Norway, April.

Ole Jorgen Liodden / First night with midnight sun in Svalbard, Norway, 17 April 2016

Ingo Arndt / Midnight sun over icefield in late winter, 80 degrees north, Spitsbergen, Svalbard, Norway, April Taken on the day of the first midnight sun of the year.

Ingo Arndt / Midnight sun over ice floes in late winter, Svalbard, Spitsbergen, Norway

Ingo Arndt / Ice floes and midnight sun, Svalbard, Spitsbergen, Norway

Ingo Arndt / Midnight sun over ice floes, Svalbard, Spitsbergen, Norway

Ingo Arndt / Midnight sun in late winter, Svalbard, Spitsbergen, Norway

Ingo Arndt / Polar Bear (Ursus maritimus) on ice under midnight sun in late winter, Svalbard, Spitsbergen, Norway

Matthias Breiter / Midnight sun, Frobisher Bay, Baffin Island, Nunavut, Canada

Matthias Breiter / Midnight sun, Frobisher Bay, Baffin Island, Nunavut, Canada

Jussi Murtosaari / Wetlands at night in midsummer, with light from midnight sunset, Parikkala, Finland, June.

Ole Jorgen Liodden / Arctic tern (Sterna paradisaea) flying towards Polar bear (Ursus maritimus) resting on rocks with golden light from the midnight sun, Svalbard, Norway. August.

Ole Jorgen Liodden / Atlantic puffin (Fratercula arctica arctica) resting with beak under wing, with midnight sun, Hornoya, Vardo, Norway, July.

Orsolya Haarberg / Midnight sun over in the spruce forest. Midnight Sun. Between Lake Riteljaure and Lake Saiva in the Sjaunja Nature Reserve, on the west side of Mt Tjakel. Laponia World Heritage Site, Swedish Lapland,...

Orsolya Haarberg / Reflections of clouds in a sea passage on Steinsundoy between Daloy and Hardbakke at midnight sunset. Solund municipality, Sogn og Fjordane, Norway. June 2012

Erlend Haarberg / View of sea fog from Lovunden mountain in midnight sun, Helgeland, Nordland, Norway, July 2009.

Wild Wonders of Europe / Widstrand / Midnight sun light over lake, Saltoluokta Area, Greater Laponia Rewilding Area, Lapland, Norrbotten, Sweden, June 2013.

Orsolya Haarberg / Silhouette of flock of Atlantic puffin (Fratercula arctica) with the Taena Archipelago in the background, Lovund, Helgeland, Nordland, Norway, midnight sun, June 2006

Mark Carwardine / Minke whale surfacing in midnight sun {Balaenoptera acutorostrata} Skjalfandi Bay,

Ole Jorgen Liodden / Polar Bear (Ursus maritimus) in arctic ice landscape with midnight sun. Nordaustlandet, Svalbard, August.

Bryan and Cherry Alexander / Group of tourists from "The Stockholm" enjoying the midnight sun on Karl XII Oya. Svalbard, Norway, June 2006.

Eric Baccega / Midnight sun light over icepack and cliffs in spring. Arctic Bay, Baffin Island, Nunavut, Canada, June.

Eric Baccega / Midnight sun light over icepack and cliffs in spring. Arctic Bay, Baffin Island, Nunavut, Canada, June.

Eric Baccega / Midnight sun light over icepack and cliffs in spring. Arctic Bay, Baffin Island, Nunavut, Canada, June.

Eric Baccega / Midnight sun light over icepack and cliffs in spring. Arctic Bay, Baffin Island, Nunavut, Canada, June.

Orsolya Haarberg / The view of Sanna (Taena) in sea fog, from the top of the Lundeura (Lovund, Luroy) in the Midnight Sun, Helgeland, Nordland, Norway, July 2009

Orsolya Haarberg / The view of the Helgeland Archipelago, including Donna and Taena, from the top of Donnamannen, in the midnight sun, Helgeland, Nordland, Norway, July 2009

Bryan and Cherry Alexander / Midnight sun reflected in calm sea off Igloolik Island. Nunavut, Canada, July, 1992.

Bryan and Cherry Alexander / Inuit hunter travelling by dog sled under midnight sun. Igloolik, Nunavut, Canada, June 1992.

Steven Kazlowski / Spring landscape of the midnight sun over an open lead in the pack ice in the Chukchi Sea, off shore from the arctic village of Barrow, Alaska. April 2009

Steven Kazlowski / Midnight sunset, over the Chukchi Sea near the coastal arctic village of Barrow, Alaska. April 2009

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Hiker crossing a river in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / River in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / River in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Stream in the midnight sun, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Sven Zacek / Waterfall in the midnight sun, white water stream in swedish forest, Sweden, Scandinavia, Summer.

Konstantin Mikhailov / Inlet shore of the White Sea, Karelia, N Russia in the midnight sun, July 2008

Michael Pitts / Svalbard, Norway, midnight sun on mountains in summer, July 2008

Jerry Monkman / Rainstorm lit by the midnight sun in the White Mountains, North of Fairbanks, near Circle Hot Springs, Pinnell Mountain Trail, Alaska, USA

Roy Mangersnes / Sabine's Gull (Xema sabini) flying in midnight sun on the arctic tundra of Barrow, Alaska, USA. June

Jorma Luhta / Peregrine falcon perched in tree, midnight sun, August, North Finland 2005

Colin Monteath / Siberian Husky (Canis familiaris) resting in polar midnight light, Greenland

Colin Monteath / Siberian Husky (Canis familiaris) group running in sled team in polar midnight light, Greenland

Tui De Roy / Broken fast ice under midnight sun and impending storm, Edward VIII Bay, Kemp Coast, east Antarctica

Theo Allofs / Large icebergs at midnight, end of June, mid summer night, Greenland

Theo Allofs / Hiker overlooking fjord covered with small pieces of ice and large icebergs, mid-summer, June, Greenland

Theo Allofs / Tourist boat in front of large iceberg at midnight, end of June, mid-summer night, Greenland

Theo Allofs / Large icebergs at midnight, end of June, mid-summer night, Greenland

Theo Allofs / Many icebergs drifting in the Arctic at midnight, end of June, mid summer night, Disko Bay, Greenland

Tui De Roy / Emperor Penguin (Aptenodytes forsteri) large chick on fast ice, midnight sun in austral spring, No-Name Rookery, Princess Martha Coast, Weddell Sea, Antarctica

Tui De Roy / Emperor Penguin (Aptenodytes forsteri) group of four on sea ice under midnight sun, Ekstrom Ice Shelf, Weddell Sea, Antarctica

Doug Allan / Midnight sun over Spring pack ice, Lancaster Sound, Canadian Arctic, Canada

Seppo Valjakka / Stoat {Mustela erminea} Northern Finland in midnight sun

Martha Holmes / Midnight sun on broken pack ice, Admiralty Inlet ice edge, Canadian Arctic

Martha Holmes / Midnight sun on broken pack ice, Admiralty Inlet ice edge, Canadian Arctic