Eric Dragesco / A view of the mountainous habitat of the Markhor. Naryn National Park, Kyrgyzstan, Central Asia, November 2009.

Vincent Grafhorst / Southern Giraffe (Giraffa giraffa) silhouetted against the setting sun, Lethiau Valley, Central Kalahari Game Reserve, Botswana

Jack Dykinga / Flowering redbud (Cercis sp) in a heavily vegetated arroyo / valley in the Chihuahuan Desert, Tamaulipas, Mexico

Rolf Nussbaumer / La Paz Waterfall in Cloudforest, Central Valley, Costa Rica, Central America, December 2006

Rolf Nussbaumer / Black Guan {Chamaepetes unicolor} adult head on close up, Bosque de Paz, Central Valley, Costa Rica

Rolf Nussbaumer / Coppery-headed Emerald, Elvira cupreiceps, male in flight feeding on Spiral Ginger (Costus Pulverulentus), Central Valley, Costa Rica, Central America, December 2006

Pete Oxford / Wild yak {Bos mutus} Central Bhutan Phobjika valley

Pete Oxford / Viales Valley with Sierra Rosario Mountain Range with Mojotes (limestone tree covered knolls), UNESCO World Heritage site, North central Piar del Rio Province, Cuba, Caribbean, 2011

Christian Ziegler / Rainforest covering mountains in valley of the upper Teribe River, Volcano Baru National Park, Bocas del Toro, Panama

Eric Dragesco / A man sitting on a snowy hill above a valley searching landscape with binoculars for wildlife, Naryn National Park, Kyrgyzstan, Central Asia, November.

Inaki Relanzon / Tsaranoro, the highest wall in Madagascar, famous for climbers, in the Moranaro Valley, Andrigitra National Park, Central Madagascar, May 2010

Inaki Relanzon / Tsaranoro, the highest wall in Madagascar, famous for climbers, in the Moranaro Valley, Andrigitra National Park, Central Madagascar, May 2010

Jenny E. Ross / View of the All-American Canal, which carries Colorado River water from the Imperial Dam to the Imperial Valley. USA / Mexico border in California, December 2006

Jenny E. Ross / Large sign on Interstate 5 in California's Central Valley agricultural region, reminding the public that much of California would be a desert or semi-desert, incapable of growing crops to feed America...

Steven David Miller / Satinay / Fraser Island Turpentine tree (Syncarpia hillii) Central Station and Pile Valley, Fraser Island, Queensland, Australia

Vincent Grafhorst / Scorpion (Parabuthus stridulus) ready to attack, Central Kalahari Game Reserve, Lethiau Valley, Botswana

Vincent Grafhorst / Snouted Cobra (Naja annulifera) in tree, Central Kalahari Game Reserve, Deception Valley, Botswana

Vincent Grafhorst / Black-backed Jackal (Canis mesomelas) walking, Central Kalahari Game Reserve, Deception Valley, Botswana

Vincent Grafhorst / Rufous-naped Lark (Mirafra africana) singing on a signpost, Central Kalahari Game Reserve, Deception Valley, Botswana

Sebastian Kennerknecht / American Coot (Fulica americana) on pond, Scotts Valley, California

Steven David Miller / Satinay turpentine tree (Syncarpia hillii) Central Station and Pile Valley, Fraser Island, Queensland, Australia

Colin Monteath / St Bathan's Range from Hawkdun Range in winter, central Otago, New Zealand

Tim Laman / Aerial view of river gorge of the Rio Iladyi on the Southwest of Bioko Island, Equatorial Guinea, Central Africa, with cascades in the upper gorge visible. January 2008

Tim Laman / Aerial view of river gorge of the Rio Iladyi on the Southwest of Bioko Island, Equatorial Guinea, Central Africa, with cascades in the upper gorge visible. January 2008

Tim Laman / Aerial view of river gorge of the Rio Iladyi on the Southwest of Bioko Island, Equatorial Guinea, West Africa, with cascades in the upper gorge visible. January 2008

Jouan & Rius / River meandering though the moss, Joküldalir valley, central Iceland 2005

Shattil & Rozinski / Sign protesting against the US / Mexico border wall, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January/February 2009

Shattil & Rozinski / Construction of the border wall between USA and Mexico in a wildlife corridor, Lower Rio Grande Valley, Texas, USA ILCP RAVE January/February 2009

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County showing how wildlife corridors are severed, reduced or eliminated by the wall, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP R...

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January...

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January...

Shattil & Rozinski / Lower Rio Grande Valley wildlife corridor, Mexican side of the Rio Grande at sunset viewed from Texas, USA

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County, Texas showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE...

Shattil & Rozinski / Aerial view of the Mexico / US border wall in Hidalgo County showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January...

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January...

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January...

Shattil & Rozinski / Aerial view of the US / Mexico border wall in Hidalgo County showing how wildlife corridors are severed, reduced, or eliminated, Lower Rio Grande Valley wildlife corridor, Texas, USA ILCP RAVE January...

Andy Rouse / Hanging valley and prime Mountain gorilla habitat, Parc National des Volcans / Volcanoes National Park, Virunga Mountains, Rwanda

Sebastian Kennerknecht / California Quail (Callipepla californica) male on fence post, Santa Cruz, Monterey Bay, California

Luiz Claudio Marigo / Large formation of bromeliads {Dyckia sp} in the Valley of the Moon (Vale da Lua) Chapada dos Veadeiros, Cerrado region, Gois State, Central Brazil.

Luiz Claudio Marigo / The Vale da Lua (Valley of the Moon), rock formations eroded by the waters of So Miguel River, at Chapada dos Veadeiros, near Alto Paraso de Gois town, Gois State, Central Brazil.

Luiz Claudio Marigo / People bathing at So Miguel River in Vale da Lua (Valley of the Moon) Chapada dos Veadeiros, municipality of Alto Paraso de Gois, Gois State, Central Brazil.

Vincent Grafhorst / Sunrise over Deception Valley with silhouetted trees, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Secretary Bird (Sagittarius serpentarius) walking, Lethiau Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Springbok (Antidorcas marsupialis) fawn trying to hide, Lethiau Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Southern Giraffe (Giraffa giraffa) silhouetted against the setting sun, Lethiau Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Yellow-billed Kite (Milvus aegyptius), Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Yellow-billed Kite (Milvus aegyptius), Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Bat-eared Fox (Otocyon megalotis) nursing her young, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Springbok (Antidorcas marsupialis) fawn in Kalahari landscape, Lethiau Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Pale Chanting-goshawk (Melierax canorus) flying, Lethiau Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Bat-eared Fox (Otocyon megalotis) young lying near burrow with the mother in the background, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Springbok (Antidorcas marsupialis) female with herd in the background, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Cobra (Naja sp), Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Abdim's Stork (Ciconia abdimii) with scorpion in its bill, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Blue Wildebeest (Connochaetes taurinus) cow with calf, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Abdim's Stork (Ciconia abdimii) standing in grass, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Spike-heeled Lark (Chersomanes albofasciata) singing, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Northern Black Korhaan (Eupodotis afraoides) male on termite mound, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Gemsbok (Oryx gazella) pair, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Gemsbok (Oryx gazella) trio foraging in high Kalahari grass, Deception Valley, Central Kalahari Game Reserve, Botswana

Vincent Grafhorst / Springbok (Antidorcas marsupialis) male grazing, Deception Valley, Central Kalahari Game Reserve, Botswana

David Noton / The Cirque de Navacelles, a cut-off meander on the Gorges de la Vis, in the Cevenne region of the southern Massif Central, Languedoc, France

Michael D. Kern / Guatemalan Beaded Lizard {Heloderma horridum charlesbogerti} climbing a tree, Montagua Valley, Guatemala Venomous species

Michael D. Kern / Guatemalan Beaded Lizard {Heloderma horridum charlesbogerti} in habitat, Montagua Valley, Guatemala

Michael D. Kern / Guatemalan Beaded Lizard {Heloderma horridum charlesbogerti} climbing a tree, Montagua Valley, Guatemala Venomous species

Anup Shah / Aerial view of a crater lake in Central Island in Lake Turkana, Northern Kenya

Jack Dykinga / Bromeliad (Hechtia sp) growing on a cliff edge in the valley beneath the Sierra Madre Oriental, Mexico, Central America

Rolf Nussbaumer / Variegated Squirrel {Sciurus variegatoides} with grey head and tail and orange body, Central Valley, Costa Rica

Rolf Nussbaumer / Violet Sabrewing {Campylopterus hemileucurus} female feeding on "Snakeface" flower, Central Valley, Costa Rica

Rolf Nussbaumer / Rufous-tailed Hummingbird {Amazilia tzacatl} feeding on Heliconia Flower, Central Valley, Costa Rica

Rolf Nussbaumer / Purple-throated Mountain-gem {Lampornis calolaema} male perched, Central Valley, Costa Rica

Rolf Nussbaumer / White-nosed Coati {Nasua narica} adult walking, Central Valley, Costa Rica

Rolf Nussbaumer / Silver-throated Tanager {Tangara icterocephala} Central Valley, Costa Rica

Rolf Nussbaumer / Violet Sabrewing {Campylopterus hemileucurus} male feeding on Heliconia flower, Central Valley, Costa Rica

Rolf Nussbaumer / Purple-throated Mountain-gem {Lampornis calolaema} male perched on Banana flower, Central Valley, Costa Rica

Rolf Nussbaumer / Violet Sabrewing {Campylopterus hemileucurus} male feeding on Shrimp plant flower (Acanthaceae), Central Valley, Costa Rica

Rolf Nussbaumer / Rose-breasted Grosbeak {Pheucticus ludovicianus} immature male, Central Valley, Costa Rica

Rolf Nussbaumer / Tennessee Warbler {Vermivora peregrina} on Tree fern, Central Valley, Costa Rica

Rolf Nussbaumer / Purple-throated Mountain-gem {Lampornis calolaema} male feeding from Ginger flower, Central Valley, Costa Rica

Rolf Nussbaumer / Violet Sabrewing {Campylopterus hemileucurus} male, Central Valley, Costa Rica

Rolf Nussbaumer / Purple-throated Mountain-gem {Lampornis calolaema} male feeding from flower, Central Valley, Costa Rica

Rolf Nussbaumer / Slate-throated Redstart {Myioborus miniatus} Central Valley, Costa Rica

Rolf Nussbaumer / Purple-throated Mountain-gem {Lampornis calolaema} male feeding from Banana flower, Central Valley, Costa Rica

Rolf Nussbaumer / Prong-billed Barbet {Semnornis frantzii} Central Valley, Costa Rica

Rolf Nussbaumer / Silver-throated Tanager {Tangara icterocephala} Central Valley, Costa Rica

Rolf Nussbaumer / Violet Sabrewing {Campylopterus hemileucurus} male feeding on Spiral Ginger flower (Costus Pulverulentus), Central Valley, Costa Rica

Rolf Nussbaumer / Magnificent Hummingbird {Eugenes fulgens} male perched, Central Valley, Costa Rica

Rolf Nussbaumer / Red-tailed Squirrel {Sciurus granatensis} climbing down tree, Central Valley, Costa Rica

Rolf Nussbaumer / Collared Trogon {Trogon collaris} male, Central Valley, Costa Rica

Rolf Nussbaumer / Common Bush-Tanager {Chlorospingus ophthalmicus} Central Valley, Costa Rica

Rolf Nussbaumer / Coppery-headed Emerald, Elvira cupreiceps, female in flight on flower of the ginger family(Zingiberaceae), Central Valley, Costa Rica, Central America, December 2006

Rolf Nussbaumer / Green Hermit {Phaethornis guy} male in flight feeding on "Snakeface" flower, Central Valley, Costa Rica

Rolf Nussbaumer / Fire Star / Crucifix orchid flower {Epidendrum radicans} Central Valley, Costa Rica

Rolf Nussbaumer / Mountainstream in Cloudforest, La Paz Waterfall Gardens, Central Valley, Costa Rica, Central America, December 2006

Rolf Nussbaumer / Coppery-headed Emerald, Elvira cupreiceps, male in flight on flower of the ginger family(Zingiberaceae), Central Valley, Costa Rica, Central America, December 2006