Jack Dykinga / Sand Verbena (Abronia villosa) and Birdcage Evening Primrose (Oenothera deltoides) flowering on Pinta Sands, Sierra Pinta Mtns, Cabeza Prieta NW Refuge, Arizona, USA

Jack Dykinga / Sand Verbena (Abronia villosa) and Birdcage Evening Primrose (Oenothera deltoides) flowering on Pinta Sands, Sierra Pinta Mtns, Cabeza Prieta NW Refuge, Arizona, USA

Kirkendall-Spring / Shoreline of Lake Michigan at Sleeping Bear Dunes, Sleeping Bear Dunes NP, Michigan, USA

Jose B. Ruiz / Camelthorn tree in Namib desert {Vachellia erioloba} Sossus Vlei, Namibia

Jack Dykinga / Desert Lilly (Hesperocallis undulata) and Sand Verbena (Abronia villosa) Mohawk Dunes, Barry M. Goldwater Range, Arizona

Jack Dykinga / Cracked clay and Creosote bushes (Larrea tridentata) in Mesquite Flat sand dunes with the Grapevine Mountains in the distance, Death Valley National Park, Califronia

Shattil & Rozinski / San Luis valley, Great Sand Dunes National Park, Colorado, USA

Jack Dykinga / Petrified sand dunes with eroded cross hatch sandstone strata at dawn, Paria Canyon-Vermilion Cliffs Wilderness, Arizona, USA with first winter snow and Juniper bushes {Juniperus osteosperma}

Jack Dykinga / Petrified sand dunes with eroded sandstone striations at sunset, Paria Canyon-Vermilion Cliffs Wilderness, Arizona, USA

Jack Dykinga / Petrified sand dunes with eroded red and yellow sandstone bands, Paria Canyon-Vermilion Cliffs Wilderness, Arizona, USA, and Pointleaf manzanita {Arctostaphylos pungens}

Jack Dykinga / Sand dune patterns, Biosphere Reserve of Pinacate and Gran Desierto Altar, Sonoran desert, Mexico

Jack Dykinga / Petrified sand dunes with eroded sandstone at sunset, Paria Canyon-Vermilion Cliffs Wilderness, Arizona, USA

Richard Du Toit / Thick-tailed Scorpion (Buthidae) walking on sand dune and casting a shadow, Namib-Naukluft National Park, Namibia

Colin Monteath / Sunset from sand dunes above Mason Bay Beach, Rakiura National Park, Stewart Island, New Zealand

Richard Du Toit / Aerial view of Gemsbok {Oryx gazella gazella} galloping across sand dunes, Namib Naukluft Park, Namibia

Richard Du Toit / Aerial view of Ostrich {Stuthio camelus} running across sand dunes, Namib Naukluft Park, Namibia

HUW CORDEY / Aerial sand dunes, Sossusvlei, Namib Naukluft NP, Namibia, 2005 From BBC Planet Earth series

HUW CORDEY / Aerial view of abstract dune patterns with snow, Gobi Desert, Mongolia, January 2004. Filmed for BBC Planet Earth series.

HUW CORDEY / Domesticated Bactrian camels (Camelus bactrianus) walking across Gobi Desert, Mongolia, January 2004. From BBC Planet Earth Series.

Shattil & Rozinski / Bison {Bison bison} on sand dunes, Medano Zapata Ranch, San Luis Valley, Colorado, USA

Tony Heald / Aerial view of sand dune landscape, Namib Naukluft NP, Namibia

Hanne & Jens Eriksen / Sand dunes, Barik, Oman

Pete Oxford / Sand dunes, Sossusvlei, Namibia, Southern Africa

Pete Oxford / SAND DUNES OF NAMIB DESERT, NAMIBIA.

Tony Heald / Aerial view of Sossusvlei, Namib desert, Namibia

Philippe Clement / Devil's thorn (Tribulus zeyheri) the Kalahari desert's prominent creeper, appearing after the rains, Kgalagadi NP, South Africa

Pete Oxford / Landrover crossing sand dunes. Skeleton Coast Namibia

Hermann Brehm / Oryx in the dunes of the Namib Desert, Namibia. (Oryx gazella)

Pete Oxford / Hongoryn els or singing sands dunes up to 800m, Gobi desert, Mongolia

Tim Fitzharris / 750 foot tall sand dunes, tallest in North America, Great Sand Dunes National Monument, Colorado

Jose B. Ruiz / Female Wolf spider carries young on back, sand dunes, Spain

Jim Brandenburg / Aerial view of Namib Desert sand dunes, Namibia

Jim Brandenburg / Gemsbok (Oryx gazella) on sand dune, Namib Desert, Namibia

Jim Brandenburg / Gemsbok (Oryx gazella) running across sand dune, Namib Desert, Namibia

Jim Brandenburg / Aerial view of Namib Desert meeting Atlantic Ocean at the Skeleton Coast, Namibia

Jim Brandenburg / Landscape of sand dunes, Namib Desert, Namibia

Michael & Patricia Fogden / Peringuey's Sidewinding Adder (Bitis peringueyi) sidewinding across sand dune, Namib Desert, Namibia

Michael & Patricia Fogden / Peringuey's Sidewinding Adder (Bitis peringueyi) on sand dune, Namib Desert, Namibia

Pete Oxford / Aerial view of sand dunes, near Sossusvlei, Namibia

Jim Brandenburg / Gemsbok (Oryx gazella) on sand dune, Namib Desert, Namibia

Gerry Ellis / Star dune formations, Namib-Naukluft National Park, Namibia

Gerry Ellis / Aerial view of barchan dunes showing typical horns and downwind slip face, at approximately 32 degrees, Skeleton Coast National Park, Namibia

Gerry Ellis / Aerial view of star dune formations, Namib-Naukluft National Park, Namibia

Jim Brandenburg / Gemsbok (Oryx gazella) standing on dune, Namib Desert, Namibia

Jim Brandenburg / Gemsbok (Oryx gazella) trio running on sand dune, Namib Desert, Namibia

Jim Brandenburg / Gemsbok (Oryx gazella) walking across sand dune, Namib Desert, Namibia

Michael & Patricia Fogden / Aerial view of sand dunes along the Skeleton Coast, Walvis Bay, Namibia

Yva Momatiuk & John Eastcott / Lone hiker walking along the base of a sandstone butte strong pattern of wavy lines in petrified sand dunes are exposed by erosion, Vermilion Cliffs National Monument, Colorado Plateau, Utah

Yva Momatiuk & John Eastcott / Lone hiker walking along the base of a sandstone butte strong pattern of wavy lines in petrified sand dunes are exposed by erosion, Vermilion Cliffs National Monument, Colorado Plateau, Utah

Yva Momatiuk & John Eastcott / Lone hiker walking on colorful sandstone strong pattern of wavy lines in petrified sand dunes are exposed by erosion, Vermilion Cliffs National Monument, Colorado Plateau, Utah

Tim Fitzharris / Sand dunes and the Mittens, Monument Valley Navajo Tribal Park, Arizona

Tim Fitzharris / Gypsum dunes, Guadalupe Mountains National Park, Texas

Mark Payne-Gill / Sand dunes and desert - aerial view on the Oman / Saudi border known as 'The Empty Quarter'

GRANT MCDOWELL / Dust storm preceeding thunderstorm in the Sahel, Mali NB Person watching

David Noton / Sand dunes in the Namib-Naukluft NP, Namib desert, Namibia, Southern Africa

David Noton / Sand dune base and tree. Namib-Naukluft NP, Namib desert, Namibia, Southern Africa

David Noton / Sand dunes in the Namib-Naukluft NP, Namib desert, Namibia, Southern Africa

Jose B. Ruiz / Giant sand dunes. Namib-Naukluft NP, Namib Desert, Namibia, Southern Africa

David Noton / Sand dunes in the Namib-Naukluft NP, Namib Desert Namibia, Southern Africa

David Noton / Sand dunes in Namib-Naukluft NP, Namib Desert, Namibia, Southern Africa

Jose B. Ruiz / Sea daffodil and flying bee, coastal sand dunes, Spain

Jose B. Ruiz / Giant sand dune Sossus Vlei, Namib-Naukluft NP, Namib desert, Namibia, Southern Africa

Pete Oxford / Landrover crossing sand dunes, Namib desert, Namibia

Pete Oxford / Landrover crossing sand dunes, Skeleton Coast, Namibia

Pete Oxford / Landrover crossing sand dunes, Skeleton Coast, Namibia

Jason Venus / Desert monitor {Varanus griseus} Sahara desert

David Noton / Petrified trees, Deadvlei, Namib-Naukluft NP. Namib desert, Namibia, Africa

David Kjaer / Sand dunes, sea and rocks at Eilean na Rubha, Isle of North Uist, Scotland, UK

GRAHAM HATHERLEY / Fennec fox {Fennecus zerda} Morocco, captive

Hermann Brehm / Oryx (Oyrx gazella) in the dunes. Namib Desert, Namibia, Southern Africa

Geoff Simpson / Sand lizard male in breeding colour {Lacerta agilis} Ainsdale NNR, Lancs, UK

TJ Rich / Leopard {Panthera pardus} running along sand dune ridge, Namibia, Southern Africa

TJ Rich / Solitary Leopard {Panthera pardus} walking along sand dune Namibia, Southern Africa

TJ Rich / Leopard {Panthera pardus} walking along sand dune, Namibia, Southern Africa

TJ Rich / Leopard {Panthera pardus} walking down sand dune Namibia, Southern Africa

David Tipling / Grey seal (Halichoerus grypus) pup lying on dunes, North Norfolk, England, UK. January.

David Tipling / Grey seal (Halichoerus grypus) pup lying on dunes, North Norfolk, England, UK. January.

John Shaw / Frost on soaptree yuccas (Yucca elata) and winter morning fog, in the gypsum sand dunes of White Sands National Park, New Mexico, USA. January.

John Shaw / Soaptree yucca (Yucca elata) on the gypsum sand dunes at White Sands National Park, New Mexico, USA. January.

John Shaw / Soaptree yucca (Yucca elata) and gypsum sand dunes at sunset, with San Adres mountains in distance. White Sands National Park, New Mexico, USA. January.

John Shaw / Frost on soaptree yuccas (Yucca elata) and winter morning fog, in the gypsum sand dunes of White Sands National Park, New Mexico, USA. January.

David Woodfall / Black plastic mat, put in sand dunes to stabilize sand dunes. Rhosilli Beach, Gower, South Wales, UK, December.

Ernie Janes / Silhouette of bird watcher watching sea birds from sand dunes, Titchwell, Norfolk, England, UK, January.

Tim Fitzharris / Agave (Agave sp) in desert, White Sands National Park, New Mexico

David Woodfall / Kestrel (Falco tinnunculus) male in sand dunes with Ringed plover prey (Charadrius hiaticula), Gronant dunes, Prestatyn, Wales, UK, May.

David Woodfall / Kestrel (Falco tinnunculus) male in sand dunes with Ringed plover prey (Charadrius hiaticula), Gronant dunes, Prestatyn, Wales, UK, May.

David Woodfall / Little tern (Sterna albifrons ) feeding sand eel (Hyperoplus spp) to young chick. Gronant Dunes, Denbighshire, Wales, UK, June.

David Woodfall / Little terns (Sterna albifrons ) feeding sand eel (Hyperoplus spp) to young chick. Gronant Dunes, Denbighshire, Wales, UK, June.

David Woodfall / Little tern (Sterna albifrons ) feeding sand eel (Hyperoplus spp) to young chick. Gronant Dunes, Denbighshire, Wales, UK, June.

John Shaw / Sand dunes in house. Kolmanskop, a ghost town in the Namib desert near Luderitz, Namibia, May 2017. The town was founded in the early 1900s for diamond mining, and completely abandoned in 1954. It is...

Jack Dykinga / Ponderosa pine (Pinus ponderosa) infront of petrified sand dunes with ephemeral waterfall after autumn rains, Grand Staircase-Escalante National Monument, Utah, USA. October.

SCOTLAND: The Big Picture / Sandwood Bay and dunes, Sutherland, Scotland, UK, November.

Terry Whittaker / Fallow deer (Dama dama) grazing in sand dunes, Holland, Netherlands.

Terry Whittaker / Red fox (Vulpes vulpes), resting in sand dunes, North Holland coast, Netherlands. April.

Terry Whittaker / Fallow deer (Dama dama) on sand dunes, North Holland coast. Netherlands.