Toby Roxburgh / 2020VISION / Buyers bidding for crates of freshly caught fish at Newlyn Harbour fish auction, Cornwall, England, UK, March 2011

Alex Mustard / 2020VISION / Male fifteen spined stickleback (Spinachia spinachia) guarding its nest (not visible), Shetland Islands, Scotland, UK, June

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Martin Dohrn / Pride of fifteen Lions listening for sounds of prey animals in the night. Image taken using 'Starlight Camera' technology abnd infra red light. Serengeti NP, Ngorongoro Conservation Area, Tanzania, Ea...

Gavin Hellier / Ahu Tongariki, the largest ahu on the Island, Tongariki is a row of 15 giant stone Moai statues, Isla de Pascua / Easter Island, Rapa Nui, Chile, 2008

Gavin Hellier / Ahu Tongariki, the largest ahu on the Island, Tongariki is a row of 15 giant stone Moai statues, Isla de Pascua / Easter Island, Rapa Nui, Chile, 2008

Graham Eaton / Fifteen-spined Stickleback (Spinachia spinachia) amongst kelp, with sandeel prey. Abersoch, Wales, May.

Tom Vezo / Snow Goose (Chen caerulescens) flock flying in formation during migration, Bosque Del Apache National Wildlife Refuge, New Mexico

Alex Mustard / 2020VISION / Male Fifteen spined stickleback (Spinachia spinachia) building his nest, Note how a discarded orange piece of fishing line has been incorporated. Babbacombe Bay, Torbay, Devon, UK, April

Brent Stephenson / The fifteen Moai at Ahu Tongariki that stand facing the sea. Easter Island, October 2009.

Oriol Alamany / Giant moai statues stand erect at sunrise in Ahu Tongariki, Easter Island (Pascua or Rapa Nui), Unesco World Heritage Site, November 2004

Graham Eaton / Fifteen-spined Stickleback (Spinachia spinacha) close up, hiding in weed, Abersoch, Wales, UK.

Oriol Alamany / Silhouette of giant moai statues in Ahu Tongariki with Poike Peninsula in the background, Easter Island, Pacific ocean, November 2004

Sumio Harada / Rufous Hummingbird (Selasphorus rufus) female with fifteen days old chick, Montana

Wild Wonders of Europe / Lundgren / Sea / Fifteen spined stickleback (Spinachia spinachia) Trondheimsfjorden, Norway, February 2009

Wild Wonders of Europe / Geslin / Two male Grey seals (Halichoerus grypus) lying on the beach exhausted after a fifteen minute fight, Donna Nook, Lincolnshire, UK, November 2008

Graham Eaton / Fifteen spined stickleback (Spinachia spinachia) Cardigan Bay, Wales, UK May

Suzi Eszterhas / Bat-eared Fox (Otocyon megalotis) parent with fifteen day old pups at den, Masai Mara National Reserve, Kenya

Suzi Eszterhas / Bat-eared Fox (Otocyon megalotis) fifteen day old pup, Masai Mara National Reserve, Kenya

Ingo Arndt / Butterfish (Pholis gunnellus) or Gunnell, fifteen centimeters long, Helgoland, Germany

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running down rocky slope in desert, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) frightened horses bunch up together, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) alert horses bunch up together, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) alert horses bunch up together, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Sue Daly / Fifteen spined stickleback {Spinacha spinacha} Jersey, Channel Is, UK St Catherines

Paul D Stewart / 1806 'Kangaroo' (Macropus giganteus), a copper engraving of a keeper attempting to box a kangaroo. First image of a boxing kangaroo, now an australian national icon. From Thomas Smith, 'The Naturalist...

Rick Tomlinson / Flying Fifteen class meet the IRC yachts at the leeward mark during Cowes Week, 2001.

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) tense stallion, Fifteen Mile Herd Management Area, central Wyoming

Yva Momatiuk & John Eastcott / Mustang (Equus caballus) family band running together in desert, Fifteen Mile Herd Management Area, central Wyoming

Michael Quinton / Common Loon (Gavia immer) juvenile is left high and dry when reservoir is drained to irrigate Idaho potato fields fifteen miles away, Bergman Reservoir, Wyoming