Jack Dykinga / Backlit silver cholla cactus (Cylindropuntia echinocarpa) surrounded by California poppies (Eschscholzia californica), beneath the eroded boulders that define the park. Joshua Tree National Park, Moja...

Guy Edwardes / Calm sea with St Mary's Lighthouse in distance, Whitley Bay, Tyne and Wear, England, UK, February 2008.

Guy Edwardes / Seaweed covered rocks with Gaada Stack in background, Foula, Shetland, Scotland, UK. August, 2016.

Jack Dykinga / Storm clouds at sunset over balancing eroded boulder, Texas Canyon, Little Dragoon Mountains, Chihuahuan Desert, Arizona, USA. September.

Jack Dykinga / Indian paintbrush (Castilleja sp.) flowers amid boulders in a stream, in narrow canyon with conifers in background Grand Staircase-Escalante National Monument, Utah, USA.

Jack Dykinga / Granite Boulders in canyon, Little Dragoon Mountains in background in sunset light, Texas, USA, August.

Neil Aldridge / African penguins (Spheniscus demersus) preening themselves on rocks at the Boulders Beach colony near Cape Town, South Africa.

Juergen Freund / Dingo (Canis lupus dingo) at Devils Marbles, Northern Territory, Australia.

Christophe Courteau / Storm at 'Pointe de Pern', Ile d'Ouessant / Ushant. Nividic lighthouse visible in distance. Finistere, Brittany, France, September 2011.

Bruno D'Amicis / Apennine chamois (Rupicapra pyrenaica ornata) adult male in snowy mountain habitat. Endemic to the Apennine mountains. Abruzzo, Italy, November.

Kevin Schafer / Black-footed Penguin (Spheniscus demersus) group walking near huge stones, Boulders Beach, Cape Peninsula, South Africa

Steven David Miller / Devils Marbles, Devils Marbles Conservation Reserve, Northern Territory, Australia, June 2010