Jack Dykinga / Scalding hot water continuously spouting behind layers of mineral deposits, Fly Geyser, Black Rock Desert, Great Basin Desert, Nevada, USA

Guy Edwardes / Natural Rock Pattern, Northumberland Coast, England

Ingo Arndt / View of Badlands National Park, with shadows cast between mountain peaks, and sediment layers visible, South Dakota, USA. September 2009.

Ingo Arndt / View of Badlands National Park, with shadows cast between mountain peaks, and sediment layers visible, South Dakota, USA. September 2009.

Floris van Breugel / Bristlecone pine (Pinus aristata) abstract view of exposed and weathered wood layers, White Mountains, California, USA July

Andy Rouse / Chinstrap penguin (Pygoscelis antarcticus) group on blue iceberg, Antarctica

Floris van Breugel / Colorful layers of rock on the inside of Mount St Helens' crater, seen from the rim. Washington, USA. May 2013

Orsolya Haarberg / Layers of different coloured sedimentary rocks (sandstone, mudstone, dolomite, limestone) Vardo, Finnmark, Norway, July 2006

Jack Dykinga / Scalding hot water continuously spouting behind layers of mineral deposits, Fly Geyser, Black Rock Desert, Great Basin Desert, Nevada, USA

Juergen Freund / Small, tree-covered islet. This is a karst limestone formation with layers eaten away by water. Raja Ampat, West Papua, Indonesia, February 2010

Wild Wonders of Europe / O. Haarberg / Rainbow in Hengifoss waterfall flowing over layers of grey basalt and reddish sandy clay, Iceland, August 2008

David Tipling / Close up of side of iceberg showing layers of compacted blue ice, Southern Ocean, off Antarctica, October