A porcupine hangs on a willow tree branch, Alaska

Ski touring in the High Tauern mountain range near Bad Gastein, Austria

Rice laid out to dry in Dhamrai, Dhaka, Bangladesh

American bison in Yellowstone National Park, Wyoming

Nazaré Lighthouse atop Forte de São Miguel Arcanjo, Nazaré, Portugal

Kochelsee and Heimgarten Mountain in Bavaria, Germany

Plate-billed mountain toucan in Bellavista Cloud Forest Reserve, Ecuador

Borrego Badlands in Anza-Borrego Desert State Park, California

The Lick Observatory on Mount Hamilton, near San Jose, California

Skyline of Prague, Czech Republic

Harp seal sleeping at Jones Beach, Long Island, New York

Bonfire to celebrate New Year's Eve in 2014 in Reykjavik, Iceland

Westerheversand Lighthouse in Westerhever, Germany

Mountain goats in the Yukon, Canada

Kjell Henriksen Observatory in Svalbard, Norway

Snow buntings flock during a snowstorm in New York

Royal Pavilion Ice Rink in Brighton, England

Trees on the northern slope of Mount Khomyak in the Carpathian Mountains, Ukraine

Christmas tree at Weissensee, a small lake near Ehrwald in Tyrol, Austria

Two young male polar bears, Churchill, Manitoba, Canada