Charlie Summers / Cheetah cub (Acinonyx jubatus) on the back of juvenile Springbok (Antidorcas marsupialis) Kgalagadi Trans Border Park, South Africa

Wild Wonders of Europe / Radisics / Lake Skadar viewed from the Albanian border, with Cormorants in flight, Lake Skadar National Park, May 2008

Jack Dykinga / Aerial view of Rio Grande passing through the Boquillas Canyon with the Chisos Mountains and Big Bend National Park in the background, Texas, USA on right of river, Mexico on left of river.

Wild Wonders of Europe / Smit / River Danube flowing through the Iron Gate Gorge, on the border between Romania and Serbia, Djerdap National Park, Serbia, June 2009

Wild Wonders of Europe / Smit / Photographer, Ruben Smit, above the River Danube flowing through the Iron Gate Gorge, on the border between Romania and Serbia, Djerdap National Park, Serbia, June 2009

Wild Wonders of Europe / Popp / Semi desert with Badlands, border area to Azerbaidjan, Vashlovani National Park, Georgia, May 2008

Luiz Claudio Marigo / Iguassu Falls, Iguassu NP, border of Brazil and Argentina

Andrew Walmsley / Adult male border collie portrait, Cumbria, January

Mark Carwardine / General view towards Vietnamese border, Preah Monivong Bokor National Park, south-western Cambodia (formerly Kampuchea)

Mark Carwardine / View towards Vietnamese border, Preah Monivong Bokor National Park, south-western Cambodia (formerly Kampuchea)

Jack Dykinga / Flowering Desert sand verbena (Abronia villosa) near Arizona/Mexican border with Sierra Pinta Mountains, Cabez Prieta National Wildlife Refuge, Arizona, USA

Jack Dykinga / Cottontop cactus (Echinocactus polycephalus) at dawn, near Arizona/Mexican border with Tinajas Altas Mountains, Cabez Prieta National Wildlife Refuge, Arizona, USA

Konstantin Mikhailov / Eastern pasqueflower / Prairie smoke / Prairie crocus / Cutleaf anemone (Pulsatilla patens) in flower, Orenburgsky State Nature Reserve, Zapovednik, Orenburg Steppe Region, Russia at the border with K...

Konstantin Mikhailov / Eastern pasqueflower / Prairie smoke / Prairie crocus / Cutleaf anemone (Pulsatilla patens) in flower, Orenburgsky State Nature Reserve, Zapovednik, Orenburg Steppe Region, Russia at the border with K...

Konstantin Mikhailov / Iris (Iris humilis) two in flower, Orenburg steppe Orenburgsky State Nature Reserve, Zapovednik, Orenburg Steppe Region, Russia at the border with Kazakhstan, May 2010.

Konstantin Mikhailov / Iris (Iris humilis) in flower Orenburg steppe Orenburgsky State Nature Reserve, Zapovednik, Orenburg Steppe Region, Russia at the border with Kazakhstan, May.

Konstantin Mikhailov / Iris (Iris humilis) in flower Orenburg steppe Orenburgsky State Nature Reserve, Zapovednik, Orenburg Steppe Region, Russia at the border with Kazakhstan, May.

Konstantin Mikhailov / Fratilllary / Missionbells (Fritillaria ruthanica) in flower, Orenburg steppe Orenburgsky State Nature Reserve, Zapovednik, Orenburg Steppe Region, Russia at the border with Kazakhstan, May.

Konstantin Mikhailov / Preserved wild hilly steppe with feather-grasses and other Graminea, wormwood, sagebrush, tulips, pasqueflower, crossed with brook valleys with alder-tree groves and thick bush, Orenburgsky State Natu...

Konstantin Mikhailov / Preserved wild hilly steppe with ravines and white birch groves, Orenburgsky State Nature Reserve, Zapovednik, South Ural Steppe Region, Russia at the border with Kazakhstan, May 2010.

Konrad Wothe / Cascades of the Iguacu Falls, the world's largest waterfalls, Iguacu National Park, border of Brazil and Argentina

Konrad Wothe / Cascades of the Iguacu Falls, the world's largest waterfalls, with rainbow, Iguacu National Park, border of Brazil and Argentina

Bert Willaert / Open gold mine at the border of the Atewa Forest Reserve. Ghana, September.

Georgette Douwma / Red starfish with soft coral on border of mangrove and coral reef. Raja Ampat, Indonesia.

Matthew Maran / Sign by a road at the border of the Pacific Rim National Park Reserve. West coast of Vancouver Island, Canada, October.

Barrie Britton / Heaven Lake on border between China and North Korea, Mount Changbai National Park, North-east China. Picture taken during filming for BBC "Wild China" TV Series, July 2006.

Robert Thompson / Clouded border moth (Lomaspilis marginata) (form diluta) resting on moss and lichen, Killarney National Park, County Kerry, Republic of Ireland, April

Peter Lewis / Dawn over Exmoor on the Somerset-Devon border, England, UK. June 2009

Justine Evans / Alpha-male White-handed gibbon (Hylobates lar) sitting on branch observing a neighboring gibbon family on the border of his territory, "Chai" a member of study group "C", Khao Yai National Park, Thail...

Justine Evans / Alpha male White-handed gibbon (Hylobates lar) in tree observing a neighboring gibbon family on the border of his territory, "Chai" a member of study group "C", Khao Yai National Park, Thailand, Endan...

Matthias Breiter / Devils Thumb in the Stikine Icecap region of the Alaska-British Columbia border, near Petersburg, Tongass National Forest, Alaska

Matthias Breiter / Devils Thumb in the Stikine Icecap region of the Alaska-British Columbia border, near Petersburg, Tongass National Forest, Alaska

Matthias Breiter / Devils Thumb in the Stikine Icecap region of the Alaska-British Columbia border, near Petersburg, Tongass National Forest, Alaska

Matthias Breiter / Mountains on the border of Glacier Bay National Park with Muir Glacier in foreground, Alsek Ranges, Alaska

Matthias Breiter / Takhinsha Mountains on border of Glacier Bay National Park, Haines, Alaska

Shattil & Rozinski / Wetland area acquired by the Santa Ana National Wildlife Refuge showing the disruption of the US / Mexico border wall construction. Before the wall, this valuable habitat was part of an important widl...

Shattil & Rozinski / Area of wetland acquired by the Santa Ana National Wildlife Refuge showing the disruption of the US / Mexico border wall construction. Before the wall, this valuable habitat was part of an important w...

Shattil & Rozinski / Ocelot (Felis pardalis) researcher, Jody Mays, checks the condition of a male captured earlier that day, having been fitted with a radio collar, before release. Ocelot trapping program, Laguna Atascos...

Shattil & Rozinski / Ocelot (Felis pardalis) being released after having a radio collar put on, Laguna Atascosa National Wildlife Refuge, Texas, USA. The largest known population of wild ocelots in the USA lives on this r...

John Cancalosi / National border fence between Nogales Sonora Mexico (right) and Nogales Arizona USA (left)

Colin Monteath / Skiers cross Marconi Pass, Los Glaciares National Park, Patagonia, Argentina and Chile border

Colin Monteath / Fitz Roy seen from Marconi Pass, Los Glaciares National Park, Patagonia, Argentina and Chile border

Colin Monteath / West Face of Cerro Torre, Los Glaciares National Park, Patagonia, Argentina and Chile border

Colin Monteath / West Face of Cerro Torre, Los Glaciares National Park, Patagonia, Argentina and Chile border

Theo Allofs / Monkey Puzzle Tree (Araucaria araucana) forest at the border to Chile, Lanin National Park, Argentina

Matthew Maran / National Park Ranger / Border Police guarding beach against turtle theft, Turtle Islands National Park, Sabah, Malaysia

Matthew Maran / National Park Ranger / Border Police guarding beach against turtle theft, Turtle Islands National Park, Sabah, Malaysia

Jack Dykinga / Mexico / USA boundary border marker, Quitobaquita Springs, Organ pipe cactus National Monument, Arizona, USA

Ingo Arndt / Farmland along the border of Parc National Des Volcans, Rwanda

Jabruson / Aerial view of Ishasha river near the former Zaire - Uganda border, Virunga NP, Democratic Republic of Congo

Luiz Claudio Marigo / Iguassu Falls, Iguassu NP, border of Brazil and Argentina

Gerry Ellis / Sun setting behind mountains and dunes on eastern border, Namib-Naukluft National Park, Namibia

Nick Turner / Aerial view - national park boundary meets farmland, Mount Elgon NP Kenya

Nick Turner / View of Mount Elgon National Park forest bordering farmland, Kenya. 2002

Nick Turner / Border between Mount Elgon National Park and farmland, West Kenya. 2002

Matthias Breiter / Takhinsha Mountains on the border of Glacier Bay National Park, Haines, Alaska

Norbert Wu / Rainbow over Iguacu Falls, world's largest waterfalls, Brazil and Argentina border

Mark Moffett / Tourists from cities come to Tam Dao for weekends and holidays, children playing in pool near the border of Tam Dao National Park, Vietnam