Bence Mate / Green / Double-crested basilisk (Basiliscus plumifrons) running across water surface, Santa Rita, Costa Rica. Did you know? This amazing lizard is colloquially known as the 'Jesus Christ lizard' for i...

Richard Du Toit / Greater Double-collared Sunbird (Nectarinia afra) male on Pincushion (Leucospermum sp) flower, Western Cape, South Africa

Tony Wu / Humphead parrotfish (Bolbometopon muricatum) shoal spawning in early morning, part of mass aggregation of thousands of fish. Caroline Islands, Palau.

Gary Bell/ Oceanwide / Painted Sweetlips (Diagramma pictum) in Slender Cardinalfish (Rhabdamia gracilis) school near Double-headed Maori Wrasse (Cheilinus undulatus), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Double-headed Maori Wrasse (Cheilinus undulatus), Painted Sweetlips (Diagramma pictum), and Slender Cardinalfish (Rhabdamia gracilis) school, Great Barrier Reef, Queensland, Australia

Jeff Foott / Double Arch seen through Cove Arch, Arches National Park, Utah

Jeff Foott / Double O Arch, Arches National Park, Utah

Ingo Arndt / Double-crested cormorant (Phalacrocorax auritus) adult resting, close up portrait, Everglades National Park, Florida, USA. January. Finalist in the Birds Category of the GDT Awards 2015.

Ingo Arndt / Close up foot of Double crested basilisk {Basiliscus plumifrons}

Tim Fitzharris / The Windows Section from Double Arch at sunrise, Arches National Park, Utah

Tim Fitzharris / The Windows Section from Double Arch at sunrise, Arches National Park, Utah

Bence Mate / Green / Double-crested basilisk (Basiliscus plumifrons) running across water surface, Santa Rita, Costa Rica.

Erlend Haarberg / Great snipe (Gallinago media) displaying, Norway, June.

Ernie Janes / London red bus going past Big Ben and the Houses of Parliament at Westminster, London, June 2013.

Kevin Schafer / Southern Double-collared Sunbird (Cinnyris chalybeus) male on Pincushion (Leucospermum sp) protea flower, Kirstenbosch Garden, Cape Town, South Africa

Juan Carlos Munoz / Double-crested Cormorants (Phalacrocorax auritus) and Brown pelicans (Pelecanus occidentalis) on small island, Isla Contoy National Park, Quintana Roo, Yuccatan Penninsula, Mexico

Bence Mate / Double head portrait of Great white egrets (Ardea alba) in courtship posture, Lake Csaj, Kiskunsagi National Park, Hungary

Bence Mate / Green / Double-crested basilisk (Basiliscus plumifrons) running across water surface, Santa Rita, Costa Rica

Martin Willis / Southern Double-collared Sunbird (Cinnyris chalybeus) on Rocket Pincushion (Leucospermum reflexum) flower, Kirstenbosch Garden, Cape Town, South Africa

Juan Carlos Munoz / Double Breasted Cormorant (Phalacrocorax auritus) resting beak in plumage. Everglades National Park, Florida, USA, February.

Nick Upton / Double decker bus passing peeling bark of pollution resistant London Plane Tree (Platanus x hispanica), Euston Road, London, UK, May. 2012. No release available.

Erlend Haarberg / Male Great snipe (Gallinago media) calling during display, Sor-Trondelag, Norway, May

Erlend Haarberg / Male Great snipe (Gallinago media) displaying, Norway, June

Kevin Schafer / Southern / Double-wattled cassowary (Casuarius casuarius) wild, chick moving through rainforest, Atherton Tablelands, Queensland, Australia, November

Kevin Schafer / Southern / Double-wattled cassowary (Casuarius casuarius) wild, adult male rear view, neck feathers, Atherton Tablelands, Queensland, Australia, November

Kevin Schafer / Southern / Double-wattled cassowary (Casuarius casuarius) wild, adult male rear view, Atherton Tablelands, Queensland, Australia, November

Kevin Schafer / Southern / Double-wattled cassowary (Casuarius casuarius) wild, adult male with chick in rainforest, Atherton Tablelands, Queensland, Australia, November

Kevin Schafer / Southern / Double-wattled cassowary (Casuarius casuarius) wild, adult male feeding on mushroom from tree trunk, Atherton Tablelands, Queensland, Australia, November

Kevin Schafer / Southern / Double-wattled cassowary (Casuarius casuarius) wild, adult male portrait, Atherton Tablelands, Queensland, Australia, November

Andy Rouse / African elephant (Loxodonta africana) with double rainbow in background, Masai Mara GR, Kenya, January

Mark Hamblin / 2020VISION / View from Stac Polliadh with double rainbow and rain clouds over Cul Mor, Coigach, Highland, Scotland, November. Photographer quote: "Standing on a rain lashed and windswept mountain side all morning...

Eric Baccega / Double crested cormorant (Phalacrocorax auritus) swimming on water at sunset, Cap Breton Highlands National Park, Nova Scotia, Canada, September

Kevin Schafer / Southern / Australian / Double-wattled cassowary (Casuarius casuarius) male, Atherton Tablelands, Queensland, Australia, Wild, Vulnerable species

Floris van Breugel / Twilight view of Mt. Rainier, under a clear night filled with stars, and alpine meadow of Lupins (Lupinus) in the foreground Mt. Rainer National Park, Washington, USA. August 2008. Double exposure.

Vincent Grafhorst / Double rainbow over Kalahari, Kgalagadi Transfrontier Park, Botswana

Petra Wegner / Great Dane, black coated bitch, and Magyar Vizsla /Hungarian Pointer, tan coated male, double portrait in profile together.

Nick Garbutt / King Penguins (Aptenodytes patagonicus) double head portrait, one some distance behnid the other, on the beach at Salisbury Plain, South Georgia, South Atlantic. January.

Aflo / Y-11106 Double rainbow over sea with waves breaking on shoreline

Aflo / Y-11004 Double rainbow over hillside vegetation, Waimea Canyon, Hauai, Hawaii

Aflo / Y-11001 Double rainbow on horizon over sea

Aflo / N-14405 Double waterfall in woodland, Tochigi, Japan.

Edwin Giesbers / Snow leopard (Panthera uncia) at night with full moon, double exposure, captive

Neil Lucas / Weddell seal (Leptonychotes weddellii) male surfacing in ice hole, McMurdo Sound, Ross Sea, Antarctica, November 2008

Wild Wonders of Europe / Máté / Two Great snipe (Gallinago media) near the Prypiat river, Belarus, June 2009

Wild Wonders of Europe / Máté / Great snipe (Gallinago media) near the Prypiat river, Belarus, June 2009

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) calling, Matsalu National Park, Estonia, May 2009

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) in long grass, Matsalu National Park, Estonia, May 2009

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) in long grass, Matsalu National Park, Estonia, May 2009

Wild Wonders of Europe / Rautiai / Great snipe (Gallinago media) calling, Matsalu National Park, Estonia, May 2009 WWE BOOK. WWE INDOOR EXHIBITION

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) calling, Matsalu National Park, Estonia, May 2009

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) shaking head calling, Matsalu National Park, Estonia, May 2009

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) calling, Matsalu National Park, Estonia, May 2009

Wild Wonders of Europe / Rautiainen / Great snipe (Gallinago media) in grassland, Matsalu National Park, Estonia, May 2009

Edwin Giesbers / Double crested basilisk / Green basilisk lizard (Basiliscus plumifrons), Costa Rica

Tim Fitzharris / Double-crested Cormorant (Phalacrocorax auritus) drying its wings, North America

David Kjaer / Double rainbow, viewed from Spread Eagle, Dorset, England

Kim Taylor / Red banded leaf hopper (Graphocephala coccinea) jumping, double exposure. Captive, UK

Gabriel Rojo / Double collared seedeater {Sporophila caerulescens} La Pampa, Argentina

Chris Newbert / Double-headed Maori Wrasse (Cheilinus undulatus) swimming over coral reef, Red Sea, Egypt

Norbert Wu / Elephant Ear Sponge (Ianthella basta) with schools of Black-tipped Fusiliers (Pterocaesio digramma) swimming behind, Solomon Islands

Tim Fitzharris / Double rainbow over Boulder Mountains after a storm, Idaho

Terry Andrewartha / Male great snipe fighting at lek {Gallinago / Capella media} Poland Europe

Mark Payne-Gill / Three banded armadillo rolling up into defensive ball {Tolypeutes tricinctus}. Very tough skin consists of double layer of horn and bone

Alex Mustard / African pompano (Alectis ciliaris) juvenile with long trailing dorsal and anal fins, swimming in mid-water at night. In-camera double exposure. Anilao, Batangas marine protected area, Luzon, Philippin...

David Pike / Marsh woundwort (Stachys palustris), close up. Harpers Ponds, near Double Locks, Exeter, Devon. July. Focus stacked image.

Mike Read / Motor boats going under Twin Sails Bridge, Poole Harbour, Dorset, England, UK. September 2018.

Chris Mattison / Double pylon supporting Prince of Wales Bridge, suspension bridge carrying M4 motorway across River Severn between Monmouthshire, Wales and Gloucestershire, England, UK. 2018.

Chris Mattison / Double pylon supporting Prince of Wales Bridge, suspension bridge carrying M4 motorway across River Severn between Monmouthshire, Wales and Gloucestershire, England, UK. 2018.

Magnus Lundgren / Wild Wonders of China / Hummingbird bobtail squid (Euprymna berryi) Green Island, a small volcanic island in the Pacific Ocean , Taiwan

John Chan / California brown pelicans (Pelecanus occidentalis) preening, with Double-crested cormorants (Phalacrocorax auritus) roosting nearby, Southern California, USA, June.

John Chan / Flock of California brown pelicans (Pelecanus occidentalis) and Double-crested cormorants (Phalacrocorax auritus) taking off, Southern California, USA, June.

Gary Bell/ Oceanwide / Double-headed Maori Wrasse (Cheilinus undulatus), Great Barrier Reef, Queensland, Australia

George Sanker / Double-crested cormorant (Phalacrocorax auritus) feeding on Catfish (Siluriformes). Myakka River State Park, Florida, USA. February.

Theo Bosboom / Double rainbow just after sunrise photographed at Playa de Portizuelo near Luarca, Asturias, Northwest Spain. November 2016

Heather Angel / Southern double-collared sunbird (Cinnyris chalybeus), male nectaring on Pincushion protea (Leucospermum cordifolium). Cape, South Africa. August.

Heather Angel / Southern double-collared sunbird (Cinnyris chalybeus), male nectaring on Pincushion protea (Leucospermum cordifolium). Kirstenbosch National Botanical Garden, Cape Town, South Africa. August.

Jeff Foott / Double Arch seen through Cove Arch, Arches National Park, Utah

Jeff Foott / Double Arch,a pothole arch, Arches National Park, Utah

Jeff Foott / Rock arch, Double O Arch, Arches National Park, Utah

Shane Gross / Double-ended Pipefish (Syngnathoides biaculeatus) hides in a struggling seagrass meadow near Malapascua, Philippines.

Nick Hawkins / Doube-crested cormorants (Phalacrocorax auritus) roosting on the Bird Islands off Cape Dauphin, Nova Scotia, Canada. July.

Marie Read / Pileated woodpecker (Dryocopus pileatus) male excavating in search of food, New York, USA. Digital composite.

Pascal Kobeh / Reef with hard corals, with on the foreground (Leptoseris sp), a moon coral (Diploastrea heliopora) in the background and on the right Acropa tables coral (Acropora sp.) Sulu Sea, Philippines

SCOTLAND: The Big Picture / Double rainbow emmerging from rain shower over Loch Awe, Assynt, Scotland, UK, November 2016.

Sven Zacek / Full moon with Roe deer (Capreolus capreolus) buck silhouetted below in meadow. Viljandimaa, Central Estonia. July 2018. Double exposure

Ann & Steve Toon / Southern double-collared sunbird (Cinnyris chalybeus), Kirstenbosch National Botanical Garden, Cape Town, South Africa, September

Chase Dekker / Stars above Double Arch, Arches National Park, Utah

Paul Williams / Double rainbow over traditional gers / yurts, steppe grassland, Altanbulag, Mongolia, June 2017.

David Fleetham / Bumphead parrotfish (Bolbometopon muricatum), Yap, Micronesia.

Tim Fitzharris / Double rainbow over shrubland, Apishapa State Wildlife Area, Colorado

Werner Bollmann / Haircap moss (Polytrichum sp) double exposure taken in nearly complete darkness, Norra Kvill NP, Sweden. May.

Claudio Contreras / Brown Pelican (Pelecanus occidentalis) and Double-crested Cormorant (Phalacrocorax auritus), Guerrero Negro, El Vizcaino Biosphere Reserve, Baja California, Mexico, March

Claudio Contreras / Double-crested cormorant (Phalacrocorax auritus) flying, Magdalena Bay, Baja California, Mexico, February

Felis Images / Double-whip cobra lily (Arisaema speciosum) flower, Sikkim, India, May.

Ashley Cooper / Bus on the Dunmail Raise in a blizzard, Lake District, England, UK. December 2010

Ashley Cooper / Snow plough on Dunmail Raise, Lake District, England, UK. December 2010