David Woodfall / Cheviot sheep grazing eroding machair at front of sand dunes, North Uist, Scotland, UK, June.

Juan Carlos Munoz / Eroded sandstone patterns on walls of Lower Canyon, Antelope Canyon, Page, Arizona, USA, February 2015.

Juan Carlos Munoz / Horseshoe Bend in the Colorado river, near Page, Arizona, USA, February 2015.

Juan Carlos Munoz / Toadstool shaped hoodoo a sunset, Grand Staircase-Escalante National Monument, Utah, USA, February 2015.

Steve O. Taylor (GHF) / Loss of topsoil in deforested land, Central Kalimantan, Indonesian Borneo. June 2010.

Paul Williams / View from plane of eroded salt dome, Kavir Desert, Iran, December.

Floris van Breugel / Ice cave with melt water running through, Mendenhall Glacier, Juneau, Alaska, USA, August 2014.

Hougaard Malan / Tugela falls surrounded by clouds on a misty morning. Royal Natal National Park, Drakensberg, South Africa. November 2010.

Hougaard Malan / Waterfall over deep, narrow gorge. Magwa Falls, Pondoland, Eastern Cape, South Africa. June 2012.

Hougaard Malan / Waterfall and autumn foliage with view to Mount Fitz Roy. El Chalten, Patagonia, Argentina. April 2013.

Floris van Breugel / Zebra Slot Canyon, Escalante National Monument, Utah, USA, November 2010.

Peter Cairns / Mangerstadh beach, Isle of Lewis, Scotland, April 2013.