Jorma Luhta / Cross country skier and aurora borealis colours in night sky, northern Finland, winter

Mark Hamblin / 2020VISION / Cross-country skier on snow. Cairngorms National Park, Scotland, December 2011.

Shattil & Rozinski / Cross country skier, skiing with two dogs, Brush Creek Ranch, Saratoga, Wyoming, USA, February 2010

Jeff Vanuga / Cross Country Skier's pause to watch Bison {Bison bison} moving through the Upper Geyser Basin in winter, Yellowstone National Park, Wyoming, USA, January 2008

Jeff Vanuga / Cross country skier's watching Bison {Bison bison} in the Upper Geyser Basin, Yellowstone National Park, Wyoming, USA, January 2008

Niall Benvie / Cross country skier amongst trees laden with snow, Finland

Juan Carlos Munoz / Cross country skiing through the Gran Paradiso NP, Valnontey, Aosta valley, Italian alps.

Tim Laman / Skier Phil Atkinson skiing past Rimrock Lake, Beartooth Mountains, Montana, USA May 2008

Jerry Monkman / Cross country skiing on the Carriage Roads next to Jordan Pond and the Bubbles, Acadia NP, Maine, USA

Jorma Luhta / Cross country skier with back pack, February, Riisitunturi national park, Lapland, Finland

Jorma Luhta / Cross country skier, February, Riisitunturi national park, Lapland, Finland

Larry Michael / Cross country skier, Wisconsin, USA