Alex Mustard / A diver explores Silfra Canyon, a deep fault filled with fresh water in the rift valley between the Eurasian and American tectonic plates at Thingvellir National Park, Iceland. May 2011. In this phot...

Uri Golman / Head portrait of photographer Uri Golman in temperatures of -40 degrees celsius, with frost in his beard. Greenland. March 2009. Model released

Jami Tarris / Golden Eagle (Aquila chrysaetos) huntress, Altai Mountains, Bayan Ulgii, Mongolia

Jami Tarris / Caribou (Rangifer tarandus) entering teepee for food, Khovsgol, Mongolia

Gary Bell/ Oceanwide / Surfer, Solitary Islands Marine Park, New South Wales, Australia

Jeff Foott / Hiker near waterfall and rainbow, Nevada Fall, Yosemite National Park, California

Piotr Naskrecki / Flat Rock Scorpion (Hadogenes granulatus) and hand, Gorongosa National Park, Mozambique

Piotr Naskrecki / Longhorn Beetle (Tithoes confinis) on hand, Gorongosa National Park, Mozambique

Piotr Naskrecki / Grasshopper (Tropidacris cristata) on hand, Costa Rica

Suzi Eszterhas / Mallard (Anas platyrhynchos) rehabilitator, Isabel Luevano, with one day old orphan duckling, International Bird Rescue, Fairfield, California

Yva Momatiuk & John Eastcott / Ice climber scaling Skaftafellsjokull Glacier, Skaftafell National Park, Iceland

Yva Momatiuk & John Eastcott / Ice climber scaling Skaftafellsjokull Glacier, Skaftafell National Park, Iceland