Bryan and Cherry Alexander / Bands of sorted stones running downhill, caused by frost and solifluction. Hurry Inlet, East Greenland, September 2005.

Bryan and Cherry Alexander / Light catches an area of solifluction and erosion in the Dombrava River Valley. Hurry Inlet, Scoresbysund, East Greenland, September 2005.

Jeff Wilson / View through the porthole of science teams and Frozen Planet film crew working on the sea ice in the Bering Sea, Alaska, USA, March 2008. The film crew were in search of Spectacled eider ducks, temper...

Alex Mustard / Diver seen through a porthole of the USS Kittiwake (US Military submarine rescue vessel) Photograph was taken shortly after the wreck was deliberately sunk as an attraction for scuba divers, Caribbea...

Merryn Thomas / Open porthole aboard Bristol Pilot Cutter "Morwenna", with sign "Do not open at sea". Bristol Floating Harbour, UK. April 2009.

Nick Upton / "Porthole" window carved through granite rocks by wind, weather and sea erosion. Campomoro Point, near Propriano, Corsica, France, June 2010.

Nick Upton / "Porthole" window carved through granite rocks by wind, weather and sea erosion. Campomoro Point, near Propriano, Corsica, France, June 2010.

Roy Mangersnes / The first sight of South Georgia from boat window, Southern Ocean, Antarctica. November

Jan Vermeer / View through a porthole of the Professor Molchanov, Antarctica